Geology of the country around Chapel en le Frith. Explanation of one-inch geological sheet 99, New Series

By I. P. Stevenson, MonograptusSc. and G. D. Gaunt, B.Sc. Palaeontology by Monograptus Mitchell, MonograptusA., W. H. C. Ramsbottom, Ph.D. and Monograptus A. Calver, MonograptusA. Petrography by R. K. Harrison, MonograptusSc.

Bibliographic reference: Stevenson, I.P. and Gaunt, G.D. 1971. Geology of the country around Chapel en le Frith (Explanation of one-inch geological sheet 99, New Series).  Memoirs of the Geological Survey of Great Britain England and Wales. London : HMSO.

Natural Environment Research Council. Geological Survey of Great Britain. Institute of Geological Sciences

Memoirs of the Geological Survey of Great Britain England and Wales

London Her Majesty's Stationery Office 1971 © Crown copyright 1971 SBN 11 880115 5 * Printed in England for Her Majesty's Stationery Office by Hull Printers Ltd., Willerby, Hull HU10 6DH

The Institute of Geological Sciences was formed by the incorporation of the Geological Survey of Great Britain and the Museum of Practical Geology with Overseas Geological Surveys and is a constituent body of the Natural Environment Research Council

(Front cover)

(Rear cover)

Preface

The district represented on the New Series One-inch Geological Sheet 99 (Chapel en le Frith) was first geologically surveyed by E. Hull, John Phillips and W. W. Smyth. Old Series maps were published in 1852 (81 NE and 81 SE) and 1864 (81 NW and 81 SW). Subsequent additions by A. H. Green, C. le Neve Foster, J. R. Dakyns and E. Hull were published in 1866, 1867 and 1874. The western part of the district was described in a memoir by Hull and Green published in 1866 and the remainder in 1887 in a memoir by A. H. Green, C. le Neve Foster and J. R. Dakyns.

Small marginal areas of the Chapel en le Frith sheet were surveyed during work on adjoining sheets between 1927 and 1950. Systematic fieldwork was started in 1951 by Mr. I. P. Stevenson, later joined by Mr. R. A. Eden for a few seasons, and then by Mr. G. D. Gaunt, with whose help the sheet was completed in 1961. The six-inch maps covered by the various surveyors are listed on p. xii. Solid and drift editions of the one-inch map were published in 1967. Part of the Chapel en le Frith district is covered by a special 1: 25,000 sheet (Edale and Castleton) published in 1969.

Mr. Stevenson has written most of the present memoir and was responsible for its compilation. Mr. Gaunt wrote parts of the Introduction and chapters on Millstone Grit Series, Pleistocene and Recent Deposits, Mineral Products and Water Supply. The memoir was edited by Mr. D. R. A. Ponsford and Dr. A. W. Woodland. Mr. Monograptus Mitchell identified fossils from the Carboniferous Limestone and contributed a chapter on the Stratigraphical Palaeontology of the series. Dr. W. H. C. Ramsbottom and Mr. Monograptus A. Calver identified fossils from the Millstone Grit and Coal Measures respectively and contributed to the relevant stratigraphical chapters. Petrography of the sedimentary and igneous rocks is by Mr. R. K. Harrison.

Thanks are given to Dr. D. E. Owen (Director) and Mr. D. Rushton, of the Manchester Museum, and to Mr. I. E. Burton, Curator and Librarian, Buxton Library and Museum, for allowing us to borrow bones of Pleistocene mammals from Doveholes; also to Dr. A. Sutcliffe, British Museum (Natural History) and Mr. H. E. P. Spencer, late of the Ipswich Museum, for examining them on our behalf.

Acknowledgement is here made to the Derwent Valley Water Board who have kindly placed a series of borehole records at our disposal and in appropriate parts of the text to many other concerns who have kindly furnished or released information.

K. C. Dunham, Director, Institute of Geological Sciences, Exhibition Road, London, S.W.7. 30th April, 1971.

List of six-inch maps

Geological six-inch maps inchided wholly or in part in the one-inch map Sheet 99 (Chapel en le Frith) are listed below together with the initials of the surveyors and the dates of survey. The surveyors were: R. A. Eden, W. N. Edwards, G. D. Gaunt, R. H. Price, J. V. Stephens, I. P. Stevenson and B. J. Taylor. Small parts of one-inch Sheet 99 are included on the following six-inch maps which are not yet complete: SJ97SE, SK07SW, SK07SE, SK17SW, SK17SE, SK27SW. Printed maps marked with an asterisk are uncoloured, or, to suit individual requirements, hand-coloured. The remaining maps are available for public reference in manuscript form.

SJ97NE*

Kettleshume

I.P.S., B.J.T.

1951,1954–55

SJ98SE*

Disley and Lyme Handley

I.P.S., R.H.P.

1949,1952–55

SJ98NE*

Mellor and New Mills

I.P.S., R.H.P.

1948–55

SJ99SE*

Chisworth

J.V.S., I.P.S., R.H.P.

1926,1948,1955

SK07NE

Dove Holes

I.P.S.

1952–59

SK07NW*

Femilee and Combs

I.P.S.

1952–57

SK08SE

Chapel en le Frith

I.P.S.

1952–57

SK08SW*

Whaley Bridge and Chinley

I.P.S.

1952–54

SK08NE

Kinder Scout

I.P.S.

1953–62

SK08NW*

New Mills and Hayfield

I.P.S.

1952–55

SK09SE

Black Ashop Moor and Coldharbour Moor

J.V.S., I.P.S., G.D.G.

1926–61

SK09SW*

Charlesworth

J.V.S., I.P.S.

1927,1954–61

SK17NE

Tideswell and Great Hucklow

I.P.S., R.A.E.

1953–61

SK17NW

Peak Forest

I.P.S.

1953–61

SK18SE

Castleton, Hope and Bradwell

I.P.S., G.D.G.

1960–61

SK18SW

Castleton and Barber Booth

I.P.S.

1956–61

SK18NE

Derwent

G.D.G.

1957–60

SK18NW

Edale Moor

G.D.G.

1958–61

SK19SE

Howden

J.V.S., G.D.G

1928–58

SK19SE

Hope Woodlands

J.V.S., G.D.G.

1928–60

SK27SE

Curbar

W.N.E., R.A.E.

1939,1947–54

SK27NE

Nether Padley

R.A.E., W.N.E.

1939–53

SK27NW

Eyam and Stoney Middleton

I.P.S., R.A.E., G.D.G., W.N.E.

1939–61

SK28SE

White Path Moss and Millstone Edge

W.N.E., I.P.S.

1939–51

SK28SW

Bamford and Hathersage

G.D.G., I.P.S., R.A.E., W.N.E.

1939–60

SK28NE

Hallam Moors

I.P.S. (see Yorkshire 293 N.E. & S.E.)

1949,1950–51

SK28NW

Bradfield, Derwent and Bamford Moors

I.P.S., G.D.G.

1949–60

SK29SE

Agden

J.V.S., I.P.S. (see Yorkshire 287 N.E. & S.E.)

1929–30, 1938–50

SK29SW

Bradfield Moors

W.N.E., J.V.S., I.P.S., G.D.G.

1928–58

Chapter 1 Introduction

Geographical setting

This memoir describes the geology of the district covered by the Chapel en le Frith (99) Sheet of the One-inch Geological Map of England and Wales.Throughout this memoir the word 'district' refers to this area. This area lies mainly in the Peak District of Derbyshire but also extends into Yorkshire in the north-east and into Cheshire in the west. The relations of the district to adjacent areas are shown in (Figure 1). Large tracts lie within the Peak District National Park. The region described lies across the axis of the Pennine uplift. The morphology, drainage and pattern of land usage clearly reflect variations in the lithology and structure of the underlying rocks. The principal physical features are illustrated in (Figure 2).

In the south, the Carboniferous Limestone outcrop forms a plateau, ranging in height from 1100 ft to just over 1500 ft on Bradwell Moor. This tract is gently dissected with some more deeply-cut valleys. Much of the drainage of this area is underground and surface streams are limited to valleys near the margin of the outcrop and to areas with perched water tables over impervious igneous rocks. Karst features such as potholes, sink-holes, caves and limestone scars are well-developed, though limestone pavements, typical of certain areas of Yorkshire, are little developed. Numerous spoil heaps and open workings along the lines of veins are the result of centuries of lead mining. In many places the lines of the more important veins stand out by virtue of the trees which have been planted along them. At the present time the working of limestone itself is producing striking modifications to the landscape.

To the north and east of the limestone area lie broad expanses of high, often peat-covered moorland, covering much of the Millstone Grit outcrop and rising to 2088 ft O.D. on the plateau of Kinder Scout, the highest point in the southern Pennines. The alternation of hard sandstones and soft shales produces ridges and hollows along the deeply incised valleys and, where the beds are inclined, a well-developed scarp and dip-slope topography is developed. Tors and craggy escarpments or 'edges' are conspicuous along the outcrops of the more massive and resistant sandstones, and collapse of the latter over shale on some steeper slopes has produced spectacular, and in certain localities still active, landslips. The moors furnish rough grazing for sheep, and grouse shooting. Afforestation is practised to stabilize valley slopes in the extensive reservoir areas in the upper Derwent valley and also furnishes a source of timber. Two small outcrops of Lower Coal Measures are present along the eastern margin of the district.

In the west, sandstones and shales of the Millstone Grit Series and Lower Coal Measures, sharply folded into the Goyt Trough and Todd Brook Anticline give rise to less elevated but more diverse scenery, with marked dip-slopes and scarps and some areas of moorland separated by stretches of largely pastoral farmland along the valleys. The availability of an abundant water supply has led to the establishment in the valleys of a number of settlements associated with the textile industry; these include Hayfield, Chinley, Birch Vale, New Mills and Whaley Bridge. Works in these places are now mainly concerned with bleaching and printing of fabrics. The town of Chapel en le Frith is the home of the large Ferodo works.

Except for a small area in the extreme north-east, where streams flow eastwards to the River Don, the eastern half of the district is drained by the Derwent and its tributaries, the Ashop, Alport and Noe, which lie in deeply incised valleys between the Millstone Grit moorlands. Water from the greater part of the limestone area also flows into the Derwent either direct or via the Wye just south of the district. Much of the Derwent catchment area within the district has been tapped to supply Sheffield and other cities in the East Midlands. Reservoirs in the extreme north-east also supply Sheffield.

With minor exceptions the western half of the district is drained by the River Goyt and its tributaries, including the Etherow which traverses the north-west corner to join the Goyt just beyond the western boundary of the district. Stockport is supplied by a number of reservoirs in the Goyt catchment area. G.D.G., I.P.S.

Historical

The earliest signs of human occupation in the district are the worked flints, including microliths, of Mesolithic age found beneath the peat on the moorlands (Armstrong 1956, pp. 99–101). Neolithic remains are scarce but include the Bull Ring, a stone circle at Dove Holes and a smaller circle at Green Low, Chapel en le Frith (Armstrong ibid, p. 105; Edwards and others 1962, p. 122). In contrast, the Bronze Age appears to have marked a sharp increase in the settlement of the district. Many hills in or near the limestone area bear tumuli dating from this period and this accounts for the prevalence of the synonym 'low' in place-names in this tract, examples being Bee Low, Hurd Low and Cow Low. Evidence of Iron Age occupation is less widespread but includes the hill forts of Mam Tor and Castle Naze.

The Romans established the town of Aquae Arnemetiae (now Buxton) on account of its thermal waters and linked it with their fort at Anavio (Brough) by a road, Batham Gate. Another Roman road, Long Causeway, ran from Stanage Pole over the Snake Pass to Glossop linking the forts of Templeborough and Melandra Castle (Bartlett and Preston 1956, p. 115). In pre-Saxon times much of the limestone area and the lower Millstone Grit ground was forest, though tree cover was probably sparse in the more exposed areas. Saxon times saw a partial clearance of the forest for agricultural purposes (Edwards and others 1962, pp. 61–2), but after the Norman Conquest the establishment of a royal hunting forest, centred about Peak Forest, stopped further clearance for a time.

The working of minerals in the district is of considerable antiquity. The first mineral to be produced was lead and the Odin Mine at Castleton has been considered by some to have been first worked by the Romans though this is more usually attributed to the Saxons. A Roman pig of lead has been found at Brough (Smythe 1940, pp. 139–45) but may have been produced elsewhere in Derbyshire. Lead working continued in many parts of Derbyshire in the Middle Ages and after the Norman Conquest was sufficiently widespread for the establishment of a special code of laws. These stem from the Inquisition of Ashbourne in 1288 (Fuller 1965, p. 378) which also established special courts, the Barmote Courts, to enforce them; these courts are still in existence today. Smelting of the lead ore was carried out in scattered hearths or 'boles' using local timber and the word 'bole' survives in place names at several localities. More recent working in the seventeenth and eighteenth centuries has been associated with the driving of drainage levels or 'soughs' to de-water the workings, the most important in the present district being Stoke Sough and Moor-wood Sough. Raistrick and Jennings (1965, pp. 276–7) state that the maximum production of lead was reached in the mid-eighteenth century.

Coal has been worked for over three hundred years in the area of the Goyt Trough. Bunting (1940, p. 156) states that workings at Fernilee were in operation in 1627. The most extensive coal working in the district was carried out in the nineteenth century at Whaley Bridge and the coal was used partly for lime burning. More recent working has been in conjunction with that of fireclays. The industry is now nearly extinct though considerable reserves remain.

Lime-burning is yet another local industry which has been long established. Bunting (ibid., pp. 297–9) states that fourteen kilns were in operation at Dove Holes in 1650. The older workings took the form of a series of closely spaced shallow excavations situated close to one or more kilns. Many of these areas have been planted with trees. I.P.S.

Geological sequence

The formations represented on the one-inch geological map and sections of the district are summarized below:

SUPERFICIAL FORMATIONS (DRIFT)

RECENT AND PLEISTOCENE

Landslips

Head

Hill Peat

Glacial Sand and Gravel

Alluvium

Boulder Clay

River Terrace, undifferentiated

Glacial Lake Deposits

SOLID FORMATIONS

CARBONIFEROUS

Thickness in feet (generalized)

COAL MEASURES (WESTPHALIAN)

Lower Coal Measures

Shales, mudstones and sandstones, including the Milnrow Sandstone and Woodhead Hill Rock (Crawshaw Sandstone in eastern area) with thin coals and seatearths and with the Gastrioceras subcrenatum Marine Band at base

up to 850

MILLSTONE GRIT SERIES (NAMURIAN)

Rough Rock Group: Yeadonian (G1)

Shales and mudstones with Rough Rock at top and the Gastrioceras cancellatum Marine Band at base

up to 430

Middle Grit Group: Marsdenian (R2)

Shales, mudstones and sandstones including Redmires Flags, Chatsworth Grit, Roaches and Corbar Grits (Ashover Grit in south-eastern area) and Heyden Rock and with the Reticuloceras gracile Marine Band at base

up to 1800

Kinderscout Grit Group: Kinderscoutian (R1)

Shales, mudstones and sandstones including Kinderscout Grit, Shale Grit and Mam Tor Beds and including the upper part of the Edale Shales with the Homoceras magistrorum Band at base

up to ?1700

Beds below Kinderscout Grit Group: Pendleian, Arnsbergian, Chokierian and Alportian (E1 to H2)

Shales and mudstones with very thin ironstones, limestones, siltstones and 'crowstones' (quartzitic sandstones), consisting of the main part of the Edale Shales with Cravenoceras leion at base

up to 990

CARBONIFEROUS LIMESTONE SERIES (DINANTIAN)

Viséan

Eyam Group (P2)

Dark, thin-bedded limestones; dark shales in upper part

180

Monsal Dale Group (D2)

Grey and dark grey limestones with Litton Tuff and Upper Miller's Dale Lava

600

Bee Low Group (D1)

Pale grey massive limestones with Lower Miller's Dale Lava

550

Woo Dale Group (S2)

Dark grey and grey thin-bedded limestones

230

Geological history

The Woo Dale Borehole (Cope 1949) supplies the only information regarding the pre-Carboniferous rocks of the Peak District. The borehole, in the Wye valley just beyond the southern boundary of the Chapel district, proved pyroelastics of probable Pre-Cambrian age overlain unconformably by 892 ft of Lower Carboniferous strata. This unconformity represents a large gap in the geological history for which details are lacking. Following the Dinantian marine transgression, it is possible to follow the development of a stable shelf area of deposition, largely coincident with the present limestone outcrops and a surrounding basinal area in which terrigenous deposits, largely muds, accumulated. Extensive vulcanicity, occurred mainly on the shelf.

Penecontemporaneous movement along the margins of the stable shelf area was associated with the development of the apron-reef at Castleton and subsequently with shallowing and the formation of knoll-reefs and flat reefs in the marginal part of the shelf area. Erosion in the marginal area gave rise to non-sequences and unconformities. In late Viséan times basinal conditions extended to the shelf area though in some areas shoals persisted on which reef-limestones were deposited. At the end of the Viséan carbonate deposition gave way everywhere to that of shales. During the Viséan, vulcanicity resulted in the extensive extrusion of lavas and, more locally, of pyroclastics.

Namurian sedimentation commenced with the deposition of marine muds though, in the case of the lowest strata, non-deposition or strongly condensed deposition occurred in the shelf area. Later the pattern of sedimentation was changed by the advance into the area of a large delta from the north giving the Mam Tor Beds, Shale Grit and Kinderscout Grit. A lesser and shorter-lived delta, from the south, produced the Roaches, Corbar and Ashover grits. Near emergence is shown by the formation of seatearths and coals, though these were better developed in later Namurian times; and less saline conditions are indicated by the presence of mussels in the Heyden Rock (R2) and higher beds. Sedimentation continued with very little change into the Lower Coal Measures, though coal deposition was more regular and frequent.

Igneous activity, probably of late Carboniferous age, resulted in the intrusion of dolerite sills into the Viséan limestones and heralded the Hercynian (Variscan) orogeny which produced the main structural features of the Chapel en le Frith district. There followed a period of mineralization when the veins, flats and pipe-veins were formed. The Hercynian mountain chain suffered peneplanation before the Permian transgression, known from adjacent areas.

Post-Carboniferous solid deposits are absent from the area though the effects of Permo-Triassic conditions are considered to have resulted in deep reddening of certain Upper Carboniferous sandstones in the western part of the area. There is otherwise no vestige of the later Mesozoic or Tertiary history of the district. Tertiary orogenic movements resulted in the uplift and doming of the area and initiated the modern topography.

During the Pleistocene the ice sheets of at least one of the earlier glaciations apparently covered the greater part of the district, but few traces of glacial activity now remain. A later and more clear-cut glaciation affected the lower, western ground, but in most places failed to extend much beyond a height of about 1000 ft on the hill slopes. At this time the remainder of the area suffered periglacial conditions with the formation of valley bulges and the deposition of sheets of solifluxion drift or head. Post-glacial deposits include peat, river-terraces, alluvium and landslip.

Previous literature

In this memoir previous research is summarized under the relevant chapter headings. Nevertheless, certain general works on the geology of the area are worthy of mention here for historical reasons.

Whitehurst (1778) first noted the general succession in the area, with limestone and interbedded toadstones overlain by shale, and the latter by 'millstone grit'.

Mawe (1802) described many features of the geology of the Castleton area and also noted the presence of toadstones. He described the working of Blue John fluorspar and listed the other mineral occurrences in the area. A more detailed description was given by Farey (1811) and this has been widely quoted in the description of the Carboniferous Limestone and Millstone Grit.

The Old Series Geological maps covering much of the area of Sheet 99 were 81 N.E. and S.E. published in 1852 and 81 N.W. and S.W. published in 1864. The first two sheets fell in the area described by Green and others (1887). The two western sheets were described by Hull and Green (1866). I.P.S.

References

ARMSTRONG, A. L. 1956. Palaeolithic, Neolithic and Bronze ages. In Sheffield and its region. Brit. Ass. Sheffield, 90–110.

BARTLETT, J. E. and PRESTON, F. L. 1956. Iron age and Roman period. In Sheffield and its region. Brit. Ass. Sheffield, 111–20.

BUNTING, W. B. 1940. Chapel-en-le-Frith. Manchester.

COPE, F. W. 1949. Woo Dale Borehole near Buxton, Derbyshire. Q. Jl geol. Soc. Lond., 105, iv.

EDWARDS, K. C., SWINNERTON, H. H. and HALL, R. H. 1962. The Peak District. London.

FAREY, J. 1811. General view of the agriculture and minerals of Derbyshire, Vol. 1. London.

FULLER, G. J. 1965. Lead-mining in Derbyshire in the mid-nineteenth century. E. Midld Geogr., 3, 373–93.

GREEN, A. H., FOSTER, C. LE NEVE and DAKYNS, J. R. 1887. The geology of the Carboniferous Limestone, Yoredale Rocks, and Millstone Grit of North Derbyshire. 2nd edit. with additions by A. H. Green and A. Strahan. Mem. geol. Surv. Gt Br.

HULL, E. and GREEN, A. H. 1866. The geology of the country around Stockport, Macclesfield, Congleton and Leek. Mem. geol. Surv. Gt Br.

MAWE, J. 1802. The mineralogy of Derbyshire. London.

RAISTRICK, A. and JENNINGS, B. 1965. A history of lead mining in the Pennines. London.

SMYTHE, J. A. 1940. Roman pigs of lead at Brough. Trans. Newcomen Soc., 20, 139–45.

WHITEHURST, J. 1778. An enquiry into the original state and formation of the Earth. London.

Chapter 2 Carboniferous Limestone Series (Dinantian)

Introduction

The Carboniferous Limestone Series crops out between Water Swallows, Castleton and Stoney Middleton. This area is the northern extremity of the Derbyshire Dome (see p. 320). Much of the outcrop is a plateau with relief much less marked than that of the Millstone Grit; dissection of this area has, however, caused the formation of valleys (dales) which provide many of the best sections of the Carboniferous Limestone Series. The presence of marginal apron-reef in the Castleton area (see p. 13) is also associated with strong topographical features.

The term 'Carboniferous Limestone Series' is here used as synonymous with Dinantian or Lower Carboniferous. All the exposed rocks of this age in the present district fall within the upper Dinantian or Viséan. The chief subdivisions of the Carboniferous Limestone used in this account are given in (Table 1), together with the major faunal subdivisions on which they are based.

The stratigraphical palaeontology is described separately in Chapter 3. The more important elements of the fauna only are given in the details while full fossil lists are quoted in Appendix 3.

In the present district the rocks of the Carboniferous Limestone Series consist predominantly of limestones with some interbedded basaltic lavas and tuffs referred to in the older literature as 'toadstones'; the total thickness exposed is about 1500 ft. Just beyond the southern margin the Woo Dale Borehole (Cope 1949, p. iv), starting at about the horizon of the lowest strata exposed in the Chapel en le Frith district, proved a further 892 ft of limestone (much intensely dolomitized) overlying pyroclastics of probable Pre-Cambrian age. In addition to the outcrop, Lower Carboniferous rocks are known at depth from the Edale and Alport boreholes.

Previous research

Whitehurst (1778, pl. i, fig. 6) first published a generalized section from Grange Mill to Darley Moor showing limestone with three beds of toadstone underlying shale and grit. Though the section lay to the south of the present district it is evident that Whitehurst intended it to apply to the whole of Derbyshire as he refers (ibid., pp. 149–50) to local names for the toadstones; at Castleton ('cat-dirt') and Tideswell ('channel'); the toadstones were considered to be lavas. Whitehurst further (ibid., p. 199) noted the presence of chert and crinoids ('entrochi' or 'screwstones') in the limestone.

Mawe (1802), in a work devoted largely to the mines of north Derbyshire, followed Whitehurst in stating that the limestone was overlain by shale. He further noted the presence of chert in the limestone at Bradwell and Middleton Dale (pp. 30–31) and of the toadstone outcrops at Wormhill and Castleton (p. 39). A description of a highly fossiliferous stone found at Foolow (pp. 29–30) and used for ornamental purposes probably refers to one of the knoll-reef limestones.

White Watson (1811) added to the knowledge of the Derbyshire Dome, though again his chief published section lay largely to the south of the present district. He also produced a series of inlaid sections across the area (Ford 1960, 4) showing, among other features, the igneous rock underlying the limestones of Middleton Dale and the presence of two lavas between Peak Forest and Wardlow. The work of Farey, which also appeared in 1811, added little to the knowledge of the limestone though it also (pp. 237–9) refers to the presence within it of thick "Basaltic Beds here called Toadstones".

The first Geological Survey map of the district, Old Series 81 N.E., covered most of the limestone outcrop and was published in 1852 (revised 1866), based mainly on the work of J. Phillips. The remainder formed the northern margin of Sheet 81 S.E. by J. Phillips and W. W. Smyth, published in 1852 (revised 1866 and 1867). The explanatory memoir by Green and others (1887) gave the first clear description of the succession and named two of the subdivisions, the "Chee Tor rock" and "Miller's Dale rock" (see p. 22). The presence of a thin 'toadstone' at Dove Holes was noted and the important sections with a thin coal and seatearth in Coombsdale Quarry described (ibid., pp. 21–2). Further (p. 33) the steep marginal dips in the Castleton area were noted.

Barnes and Holroyd (1897) described the occurrence of rolled-shell beds at Castleton and elsewhere. These were attributed to a shoreline extending from Castleton to Barmoor Clough. In two papers, published in 1894 and 1907, Arnold-Bemrose described first the petrography and later the field relations of the igneous rocks. The two main lavas (the Lower and Upper lavas of Miller's Dale, see p. 23) were considered by Arnold-Bemrose to be widespread over the Derbyshire Dome. Although an over-simplification in other areas (see for example Traill 1939, pp. 859–61, for the Millclose area) Arnold-Bemrose's correlations are, for the most part, valid so far as the present district is concerned. In addition the true pyroclastic nature of the Dove Holes and Litton tuffs was recognized and the lava underlying the latter first described. The vents at Monk's Dale and Castleton (Speedwell Vent) were recorded. Arnold-Bemrose further noted, the intrusive nature of the Waterswallows, Peak Forest, Potluck and Tideswell Dale sills.

Hind and Howe (1901, p. 361) first drew attention to the faunal resemblances of the limestones of the Castleton area to those of the Cracoe knolls. They also recorded some details of the section in the railway-cutting (now disused) north of Dove Holes.

Following the publication of Vaughan's classic zonal work in the Avon Gorge (1905), Sibly (1908) was the first to apply the coral-brachiopod zones to the Carboniferous Limestone of the Derbyshire Dome. Sibly recognized three subzones in the Wye valley: the lowest, the Dibunophyllum θ (D1) Subzone, included the "Upper Toadstone" and underlying strata and was succeeded by the Lonsdaleia (D2) and Cyathaxonia (D3) subzones.

Jackson (1908, p. 309) noted the presence of a bed with fish remains in Barmoor Clough Quarry. Later (1925), in a paper concerned with the limestone-shale unconformity, he described sections between Dove Holes and Bradwell and noted the presence of Goniatites crenistria at Nun Low. In 1941 (pp. 241–2) he recorded the presence of Girvanella at the base of the D2 limestones and of the underlying D1 coral band in Pin Dale; the reef-limestones at the northern end of this section were regarded as the lateral equivalent of the bedded D2 succession.

Morris (1929) gave a detailed description of the succession in Middleton Dale and Coombs Dale. Beneath the exposed beds he recognized the presence of basalt, though he confused this with the Upper Lava of Miller's Dale. Morris further noticed the presence of the Linen Dale knoll and the knoll-affinities of the highest beds in Middleton Dale. The latter were referred to a probable "D3" age and the underlying beds were placed in D2. Morris published extensive faunal lists.

Fearnsides and Templeman (1932) described the succession in a borehole at Hope, including a thick development of pillow lavas beneath basal Namurian.

In a series of papers, published between 1933 and 1939, Cope discussed the succession in the Wye valley just south of the present district. This succession is the type sequence for all but the highest beds of the shelf facies. A particularly important feature of this work was the recognition of the S2 age of the lowest beds.

Shirley and Horsfield (1940) mapped the Castleton–Bradwell area and interpreted the reef-limestones with a B2 goniatite fauna as lying with marked unconformity against a cliff of standard limestones. The outward dips of the reef-limestones were interpreted as largely depositional. The succession in the standard limestones was also described, the presence of two bands with Davidsonina septosa recorded, and the Cave Dale Lava recognized as the Lower Miller's Dale Lava. In the higher beds the presence of a band with Girvanella at the base of D2 was noted and near the top of the zone two coral bands, a lower with Lonsdaleia duplicata and, some 30 ft higher, an upper band with Orionastraea were discovered. The same authors (1945) described the structure and ore deposition of the Eyam area and gave details of the succession in Middleton Dale where the uppermost beds, the Eyam Limestones, of P2 age, were stated to rest unconformably on D2. The sequences in Coombs Dale and Cressbrook Dale were also determined and the presence above the Litton Tuff of an algal band with Girvanella nodules, the Upper Girvanella Band, noted in the latter.

Shirley and Horsfield's conclusions in the Castleton area were attacked by Parkinson in a series of papers (1943, 1947, 1953). This author argued on faunal grounds and from field relations that the postulated unconformity was absent, or at the most a local non-sequence, and that the B2 and P1 reef-limestones were the lateral equivalents of the D1–D2 standard succession. Ford (1952) described the geology of certain caves in the Castleton area, which supported lateral passage of reef to standard limestone.

Hudson and Cotton (1945a, 1945b) described the succession in the Alport and Edale boreholes. Their work has provided the only description of the beds of the basinal area within the present district and has been quoted in detail below.

As a result of a study of the palaeoecology of the Castleton reef-belt Wolfenden (1958) discovered the presence of wall-like masses of algal limestone at the junction of the fore-reef limestones (see p. 18) with back-reef limestones forming a transition to those of the shelf area. This arrangement clearly showed the lateral passage from the fore-reef limestones to those of the shelf and represented a great advance in the understanding of the morphology of the reef-belt.

The origin of the 'Beach Beds' of the Castleton area has been discussed by Sadler (1964), who concluded that they represented material deposited contemporaneously with the fore-reef limestones at the foot of a submarine channel.

Eden and others (1964) dealt with the detailed stratigraphy of Pin Dale and the area of Earle's Quarry, Hope, and this work has been extensively referred to below. Some of the more important points in this paper are the proof of the presence of a bed of tuff, the Pindale Tuff, beneath both reef and shelf facies (thus giving final proof of the absence of unconformity between these) and the description of detailed stratigraphical variation in the shelf facies adjacent to the reef-belt, including the presence of large knoll-reefs in the upper part of D2.

Parkinson has recently (1965) summarized his own work and that of other authors on the reef-belt and has postulated a break within the B2 apron-reef.

Sedimentation

There is a general structural division in the present district between the Carboniferous Limestone outcrop, forming the northern part of the broad uplift of the Derbyshire Dome, and the neighbouring down-warped or synclinal region of Kinder Scout and the Goyt–Todd Brook area. The structure of these areas is considered in greater detail on pp. 320–8. It is now generally accepted (see p. 320 and Kent 1966, p. 338) that a stable block of Lower Palaeozoic or Pre-Cambrian rocks, similar to the Alston and Askrigg blocks farther north, underlies the Derbyshire Dome. As in the case of the northern blocks, this is inferred to have exercised a considerable influence on sedimentation during Lower Carboniferous times and this effect continued on into the Namurian (seep. 161).

The above structural entities correspond to two main types of Viséan sedimentation (see (Figure 3)) and special local marginal conditions (see below) lead in places to the development of a third.

Shelf Province

This, developed in the area of the stable block, is marked by a sequence of predominantly pale massive limestones with a coral-brachiopod fauna comparable with that of the Great Scar Limestone on the Askrigg Block (see for example Rayner 1953, p. 249). Argillaceous sediments are, for the most part, rare or absent. Where the full differences between basin and shelf facies are developed, as in the Widmerpool Formation of the Duffield area, the thickness of these beds is noticeably less than that of corresponding beds of basin facies (see for example Ann. Rept. Inst. geol. Sci. for 1967, 1968, p. 82). In the Chapel en le Frith district, however, the thickness variations are not marked (see (Figure 3)). The beds of shelf facies (lithofacies and biofacies) are often termed 'standard limestones' and are present over nearly all the outcrop of the Lower Carboniferous of the Chapel en le Frith area.

Basin Province

This is marked by a thick development of thin-bedded dark limestones and shales with a goniatite-bivalve fauna. Sediments of this type were formed in negative areas subject to continuing subsidence. Though it has been suggested by Rayner (1953, pp. 248–9) that subsidence rather than depth of water was the prime factor in the formation of basinal deposits there is reason to believe that in the present area the sea-floor of the basin was at least some hundreds of feet deeper than that of the shelf (see p. 18). George (1958, p. 286) attributes the differences between the two facies to both depth of accumulation and rate of subsidence. Beds of basin fades are known in the present district only at depth in the Edale and Alport boreholes north of the shelf area. To the north-west and west of the shelf area the presence of beds of basin facies may be inferred from indications at the edge of the outcrop at two points and from the proved presence outside the district of beds of this type at outcrop in Staffordshire (Prentice 1951, pp. 175–90) and in the Gun Hill Borehole (Hudson in Hudson and Cotton 1945a, p. 318). The basinal area north of the shelf has been referred to by Kent (1966, p. 337) as the 'Edale Gulf'.

Marginal Province

In the present district a marginal reef facies, separating the shelf and basin facies, is developed between Hope and Sparrow Pit, on the northern margin of the shelf area. The fauna, while manifestly shallow-water, shows affinities with that of the basin in the presence of goniatites. The development of the apron-reef (see pp. 17–8) marks the most extreme effect of the underlying margin of the block on sedimentation. At higher horizons where the apron-reef is not developed, the margin of the block was reflected in post-apron (D2 and P2) times by the development of knoll-reefs and flat reefs (see p. 18) in or near the marginal area. A fuller discussion of the deposition of reef-limestones is given on pp. 17–9.

The early relations in time of shelf and basin are uncertain, due to lack of knowledge of the lower beds, especially in the basin. The lowest beds (S2) known in detail in both shelf and basin areas, however, both show a continuous or nearly continuous limestone sequence with a coral-brachiopod fauna and only slight difference in lithology. During B2 times the establishment of the apron-reef at Castleton coincided fairly closely with greater variation in sedimentation between shelf and basin, the upper part of these beds in the Alport Borehole bearing shale partings and yielding a goniatite fauna while the lower part shows a lithology and fauna closer to those of the shelf. The greatest facies variation was in D2 times, with the deposition of 'standard limestones' in the shelf area and of thin-bedded dark limestones succeeded by shales in the basin. Near the close of Viséan times, local uplift (see p. 32) was followed by subsidence, which allowed the spread of beds of basin type (P2) on to the shelf area.

Effects of contemporaneous earth movements

Earth movements during the deposition of the Viséan rocks of the present district may be inferred from lateral facies variations, from the presence of the reef-belt and from the occurrence of unconformities. The detailed evidence is presented later under strati-graphical headings but the general sequence of events may be summarized as follows:

  1. Deep-seated movement involving the uplift of the margin of the block initiated the formation of the apron-reef. The age of this movement would be either late S2 or early D1 (Cravenian of Hudson and Mitchell 1937).
  2. Local intra-B2 (D1) movement is postulated to account for anomalous features in the structure of the apron-reef at Peaks Hill. Parkinson (1965, pp. 172–3) has suggested on faunal grounds that a widespread break in the reef succession is present at this horizon but this cannot be regarded as firmly established. There is, however, some reason to postulate movement of Dirtlow Rake in the region of the reef-belt in late B2 times (see p. 34).
  3. Pre-P2 movement; this was acute around the edges of the block resulting in angular unconformity and at one locality (p. 96) in emergence with the local formation of a thin coal and seatearth. Shirley and Horsfield (1945, p. 293) considered that widespread unconformity existed below P2 but the present work suggests that this may have been exaggerated. Movements of this age are responsible for an east-west 'pre-Namurian' fault south of Dove Holes with P2 resting on D1 limestones on its southern side (see (Figure 7)).
  4. Intra-P2 movement is represented by the unconformity at the base of the P2 shale facies or, where P2 shales are lacking, by the break between the Viséan limestones and the Namurian. There is no evidence of unconformity between the shale facies of the Viséan and Namurian. The stratigraphical evidence shows a sharp break around the edges and over the block and a probable absence of any break in the basinal area.

Where P2 beds are absent it is difficult to distinguish the effect of pre- and intra-P2 movements and it is convenient to refer to the corresponding unconformity as the 'pre-Namurian unconformity'.

Lithology and lithofacies

The lithology of the different rock types of the Carboniferous Limestone Series is summarized below though the account is somewhat restricted by the fact that it has not been found possible to undertake systematic petrographical work on the limestones, although selected thin sections have been studied. In the stratigraphical descriptions the use of petrographical terms has, in general, been avoided as this would imply a full petrographical study. An attempt is made here to provide a correlation between field and petrographical terms.

The limestones

Many of the limestones are bioclastic, crinoid debris and brachiopods being the main constituents. Corals and algae are important in some cases. Usually the main concentrations of macrofossils are on restricted horizons (coral bands and shell bands).

Shelf Province

Woo Dale Beds

The Woo Dale Beds present a mixed lithofacies showing points in common with both pale and dark facies described below from the higher divisions. The chief rock types include:

  1. Dark grey and dark grey-brown limestones (calcarenites), fine-grained and evenly bedded. In view of the association of rocks of this type with dolomites in the Wye valley (Cope 1933, p. 129), a chemical examination of these rocks in the present district was undertaken: this showed, however, only small MgO percentages (0.22 to 0.46).
  2. Grey limestones (calcarenites), well-bedded, some bioclastic and including limestones with algal nodules. A large development of pale crinoidal limestones (biocalcarenites) is present at Peak Forest, some of which are partly oolitic.
  3. Calcilutites (micrites), usually pale-coloured and either in regular beds or in large lenticular masses. The origin of the latter is uncertain though they are best considered as bioherms in which some binding organism (possibly algal) was present but has now disappeared. This would account for the maintenance of the lens form during the deposition of the adjacent well-bedded limestones.
Bee Low, Monsal Dale and Eyam groups

A striking feature is the sharp contrast between white, pale grey and grey limestone on the one hand and dark bituminous limestones on the other. Intermediate rock types are relatively rare and the distinction between the two lithofacies has been found most valuable for mapping purposes (see for example (Figure 7)).

Among limestones of the pale lithofacies the following types have been recognized:

  1. Pale massive limestones (calcarenites) are developed extensively in both D1 and D2. Some are finely oolitic though, as Wolfenden (1958, p. 881) remarked, ooliths are not very abundant. Bands with algal nodules occur at some horizons. Rubbly-weathering beds in D2 are probably developed by the diagenesis of limestones with some non-calcareous mud content leading to segregation of the latter along cracks.
  2. Pale cherty limestones show a lithology of the matrix similar to (i). The occurrence of chert is separately dealt with on p. 16.
  3. Calcilutites (micrites) occur rarely as thin and well-defined beds in D1 and near the top of D2.
  4. Oolites (other than the imperfectly developed examples noted under (i)) are of rare occurrence but have been found in the back-reef facies near Eldon Hill (see also p. 59) and in the Wardlow Mires No. 1 Borehole (see p. 93).
  5. Coarse-grained limestones (calcirudites) are especially developed in D2 and are due to the presence of coarse organic material, either crinoid debris or shell debris or both. Crinoid debris, particularly where fine, is also common in the other rock types in variable proportions.
  6. Magnesian limestones are known though uncommon in the pale lithofacies only in one horizon in D1, which may correspond to that of the Lower Miller's Dale Lava, the dolomitization being probably connected with local variations in the composition of the sea-water.

A shallow-water origin for most of the limestones of the pale facies is indicated by the presence of the rare ooliths, by local non-sequences and by rare current-bedding. The last-named is difficult to observe but has been noted in places in D1 limestones. The higher limestones of D2 and the crinoidal facies of S2 (Peak Forest Limestones) often show sorting of coarser and finer constituents. The fauna, especially the presence of algae (cf. Pettijohn 1957, p. 596) and corals (other than zaphrentoids), is also indicative of shallow-water conditions (Ager 1963, p. 41) and the faunal aspect as a whole suggests water which was well oxygenated, allowing the spread of a vigorous fossil community at certain horizons.

The dark lithofacies occurs as both the more continuous development of basin facies and intercalations in the pale facies. Typically the limestones are fine-grained, dark and bituminous. The bedding planes are closely spaced and commonly somewhat undulating. Chert is abundant. Eden and others (1964, p. 93) have remarked that the apparent fine grain of many of these rocks is deceptive; they are in fact fine calcarenites. Some coarser, crinoidal bands occur. Thin shale partings are often present, particularly in P2 where they increase in thickness in the uppermost beds giving a transition to the shale facies.

The dark facies apparently was deposited under reducing conditions with the formation of hydrocarbons and some pyrite and a variable supply of terrigenous mud. These conditions, rather than depth of water would appear to have been the controlling factors so far as deposition in the shelf area was concerned. A similar environment must have been present at greater depths in the basinal areas (the differences in depth being inferred from a consideration of the structure of the reef-belt rather than from facies differences). A marked facies-fauna is associated with these beds and includes in particular zaphrentoids with some inarticulate brachiopods and small gastropods. However, bands with a fauna common to the pale facies also occur.

Stylolites are of common occurrence in both pale and dark lithofacies. The size of the stylolite, however, usually varies with the lithology of the country rock, the largest examples (up to 9 in high) being found in pale fine-grained massive limestones while the dark facies shows only small structures. In some cases, especially in the dark limestones, there is a capping of a solution residue of hydrocarbon or argillaceous material on the stylolites. The pressure-solution origin of stylolites, as put forward by Stockdale (1922), is now generally accepted.

Basin Province

No new work has been done on rocks of this province and the essential features of the succession in the Edale and Alport boreholes are described on pp. 113–9. Certain distinctive features of the lithology are summarized below.

The dark limestones are similar to those already described from the dark lithofacies of the shelf province, though bands of relatively coarse bioclastic material are apparently foreign to the basinal environment and are here considered to be of turbidite origin. This is borne out by Hudson and Cotton's description of 'slumping' at some horizons in the Alport Borehole, for example at 1632–1642 ft (1945a, p. 287). Graded bedding has been noted in thin bands of finely crinoidal limestone in dark limestones in the Castleton Borehole.

Marginal Province

The apron-reef limestones of the Castleton area show a typical reef lithofacies and vary from calcilutites to bio-calcirudites. These rocks are discussed, together with other reef-limestones, under a general heading below. The overlying Beach Beds are a local deposit of rolled-shell limestones whose relations are discussed on p. 35.

Chert

Lenticular, tabular, or nodular chert is, in the shelf area, present in the D2 and P2 limestones of both pale and dark facies at certain moderately well-defined horizons. It also occurs exceptionally in D1 adjacent to the reef-belt (see p. 61). In the basinal area chert also occurs in the D1 and S2 zones and the distribution in these zones resembles that noted by Newell and others (1953, pp. 161–2) in the basin facies of the Permian of the Guadalupe Mountains area, Texas, where chert occurs in the basin and is absent in reef and shelf areas.

Sargent (1921, pp. 267–76) considered that the cherts were consolidated early as bedding was deflected around the nodules. He argued against an organic origin for the silica and attributed its introduction into the sea-water largely to contemporary vulcanism. The present work supports the conclusions of Pettijohn (1957, pp. 439–40) that the cherts are post-depositional and owe their origin to the early replacement of a partly consolidated rock containing diffuse silica, the latter undergoing segregation into the nodules and tabulate bands. The chert is thus in continuity with the surrounding limestones.

In some cases secondary cherts have been produced, probably by a later re-mobilisation of silica; these are most obvious in the vicinity of mineral veins though not completely restricted to this position. The colour of the chert is in most cases governed by that of the surrounding limestone. The later cherts occur as large bulbous masses often showing concentric colour banding and (rarely) as thin veins. The presence of the later cherts is linked with the frequent silicification of fossils at certain horizons. Arnold-Bemrose (1898, p. 178) also noted the presence of quartz crystals in a limestone at the Bull Ring, Dove Holes. Hydrothermal silicification is discussed on p. 310.

Other rock types

A thin coal and seatearth are present in the Coombs Dale area (see pp. 96, 98), resting on a potholed surface (see below) of Monsal Dale Beds. Their formation is clearly linked with emergence associated with the unconformity at the base of the Eyam Limestones.

Shale or mudstone is present in the highest P2 strata at outcrop and in addition in the lower P1 beds in the Edale and Alport boreholes and in thin partings in the limestones. The lithology resembles that of the Namurian shales. Other partings, or wayboards, consist of grey-green poorly bedded unfossiliferous and often pyritous clay. Sargent (1912, pp. 409–12) described similar partings from the Crich area and concluded that they were of pyroclastic origin. This view was also taken by Cope (1939, p. 62) and is accepted here. In the present area, clay from a parting in the Chee Tor Rock at Smalldale (see p. 47) is an illite mudstone with coarse pyrite and fine needles of marcasite.

Both clay and mudstone partings in the limestone usually rest on potholed surfaces (see (Plate 2B)) such as were noted by Sargent (op. cit.) and Cope (1939, pp. 61–2). The maximum depth of the potholes is about 2 ft. Clearly these features represent contemporaneous removal of the uppermost limestone surface either by solution, erosion or both during a halt in sedimentation. Actual emergence at Coombs Dale is proved by the presence of a coal and thin seatearth overlying a potholed surface.

Reef-limestones

Following Bond (1950c) the reef-limestones of the Chapel en le Frith district may be subdivided into apron-reef, knoll-reefs and flat reefs. The stratigraphy of these is considered separately on pp. 34–5.

Apron-reef

Following Eden and others (1964), the term 'apron-reef' has been extended somewhat from the original definition of Bond (1950 c, pp. 270–1). The apron-reef is a marginal facies developed between the shelf area and the basin and had been divided by Wolfenden (1958) into fore reef, reef (called algal reef in this account) and back reef, the whole being known as the 'reef-complex'.

The fore reef consists of poorly bedded limestones, commonly highly fossiliferous (some hundreds of species being recorded) but in places poorly fossiliferous and fine-grained. In referring a particular outcrop to this facies it is necessary to consider the whole of its characters including lithology, fauna and bedding. The fore reef shows outward dips (towards the basin) of 10°-40° which have been considered by Shirley and Horsfield (1940, pp. 288–9) and by most workers since, to be the original depositional dips only slightly modified by the effects of compaction and minor tectonic movement. Recent work by Broadhurst and Simpson (1967, pp. 443–8) on the inclination of sedimentary infillings of shells and limestone cavities has demonstrated that the dips of the apron are indeed of depositional origin. The difference in height between the top and bottom of the frontal slope is considered to have been about 400 ft. The fauna, though characteristic in itself, shows affinities both with basin, in the local presence of goniatites, and with standard limestones. The limestones at the foot of the reef-slope are often crinoidal. In addition to the fine-grained limestones (calcilutites), breccias occur in places particularly in the eastern outcrop, fragments up to a foot in diameter having been noted by Eden and others (1964, p. 95). Small Neptunian dykes' of pale crinoidal limestone have been observed locally at the top (higher) part of the reef. From a study of the palaeoecology of the goniatite bed at Cow Low Nick, Ford (1965, pp. 189–90) has concluded that this deposit, situated about two-thirds of the way up the frontal slope of the fore reef, was subject to gentle current action. This and the depositional slope would be incompatible with the accumulation of unconsolidated deposits. Most of the fossils in the fore reef are unworn and must be nearly in situ. Following Black (1933), Wolfenden has suggested that the fine matrix of the fore-reef limestones may represent recrystallized algal deposits, the algae having acted as sediment-binders, at least in the upper part within the range of daylight penetration.

The algal reef ('reef' of Wolfenden) occurs as a discontinuous wall-like mass of limestone with abundant stromatolitic algae (see (Plate 13A)), sponges and other fossils. Algal reefs have been noted by Wolfenden (1958, pp. 872, 879) at two levels at the point where the strong frontal dip of the reef-complex develops. Wolfenden gives the maximum dimensions as about 30 ft wide and 100 ft high. However, recent exposure of the algal reef on Treak Cliff shows a maximum width of about 250 ft locally. The algal reefs are considered to have originated as barrier-like reefs at two horizons, growth of the lower reef having been inhibited by down-warping, producing a greater depth than the algae could tolerate.

The back reef is intermediate in both lithology and fauna between the fore reef and shelf limestones and usually shows gentle inward dips towards the shelf area. The back-reef limestones are typically well bedded and often show elements of the fore-reef fauna. They are also in general more crinoidal than all but the lowest parts of the fore reef. On the inward side this facies passes gradually into standard limestones and it is the outer facies junction which is the best defined; hence both in Wolfenden's account (ibid., pp. 877, 879–80) and in the present work it has been found necessary to group them with the shelf facies for mapping purposes, though they are separately shown on (Plate 11).

Knoll-reefs

Since the original description by Tiddeman (1889) from the Craven area there has grown up an abundant literature on knoll-reefs. This has been summarized by Bond (1950a) and Black (1954). Morris (1929, pp. 49–50) first noted the presence of knoll-reefs in the district at Linen Dale. The present work has shown them to be widespread, though restricted to the peripheral area of the limestone (i.e. the margin of the block).

The outstanding features of the knoll-reefs are the presence of original quaquaversal dips and the relatively pale, poorly bedded and fossiliferous character of the rock. A detailed description of knolls in the Pin Dale area has been given by Eden and others (1964, pp. 87–9). Here they were found to be mainly developed at two horizons and to pass laterally into calcirudite bands in the bedded succession. At one locality the formation of a knoll above an earlier one has led to the development of a composite knoll over 50 ft in height.

The knolls pass into the adjacent limestones by lensing or interdigitation. Eden and others (ibid., p. 89) noted current-bedding and some breccia associated with the knolls and concluded that they "stood up as small mounds above the general level of the sea-bed". In some cases, such as the Earle's Quarry knolls and the Dove Holes knoll (see p. 65), where breccia is present in the upper part of the knoll, this is interpreted as evidence that the structure was consolidated and a true knoll, not a bank deposit as has been suggested (Earp and others 1961, p. 44) for the Clitheroe knolls. Recent work by Orme (1970a) on the Earle's Quarry knolls suggests that algae and bryozoans were the chief sediment binders. In the case of the large knoll (see p. 88) in Earle's Quarry a true biohermal origin is also suggested by the superposition of its two component knolls; the higher being more likely to be due to the re-activation of growth of a lower bioherm than to the formation of one bank deposit precisely above another. Like the apron-reef, the knolls have a rich fauna in which brachiopods are abundant.

Flat reefs

The term flat reef was suggested by Bond (1950c, pp. 271–2) for large lateral spreads of limestone of reef facies. In many cases they may represent knolls which have grown laterally to a point where they lose their knoll form. Large spreads may be formed by the coalition of several such masses.

In the present district knoll form appears to be lost in reefs over some 50 ft in thickness, upward growth being then largely replaced by lateral growth. This contrasts with the much larger knoll forms in other parts of Derbyshire, for example at High Tor, Matlock (about 100 ft) (Smith and others 1967, p. 23) and the Cracoe area (Bond 1950b, p. 172) where thicknesses of 200 ft or more are common. Probably the knolls of the Castleton–Hucklow area were limited in growth by either gentle uplift or a static sea-floor while the larger Yorkshire knolls were formed during gentle subsidence.

Formation of reef-limestones

The conception of facies variation across the reef-complex, and the establishment of an outward-dipping frontal slope requires the postulation of deep-seated movements along the edge of the block with a sharp uplift of the latter to produce the shallow-water conditions allowing the reef fauna to flourish. An alignment of small eruptive centres along the reef-belt is further evidence of deep-seated instability in this zone. The movements produced the initial shallowing which led to the formation of the apron-reef and accord with its linear character.

It is suggested that broad and less acute uplift around the edge of the block was the initial factor which led to the formation of the knoll-reefs and flat reefs. In places (see Eden and others 1964, pp. 79–81) a more restricted local uplift may have controlled knoll formation.

Volcanic rocks

Contemporaneous volcanic rocks associated with the outcrop of the Carboniferous Limestone include lavas, tuffs and agglomerates, some of the last two types occurring in vents. In addition interbedded tuffs are known in the basinal area.

Lavas

Lavas are known at three horizons within the present district; their stratigraphy (see pp. 23–8) and petrography (pp. 119–23) are discussed separately, The rocks are olivine-basalts typically highly vesicular with calcite and chlorite-filled amygdales. In places the lavas are non-vesicular, harder, darker and more coarsely crystalline. The occurrence of pillow lavas was noted by Fearnsides and Templeman (1932, pp. 102, 107–10) in a borehole at Hope. Pillow structure is, however, not a normal feature and appears in this instance to be connected with the extrusion of lava on the marginal slope between shelf and basin at a greater depth than that at which the other lava flows, on the shelf area, were formed. The conditions under which the lavas of the shelf were extruded are uncertain though the associated sediments suggest a shallow-water origin. The thicker flows may have built up above sea-level though this cannot certainly be established.

A small thickness of clay ('toadstone clay') is in many cases present above or below the lavas. It is invariably highly altered and it is uncertain whether it is derived directly from the overlying flow or whether it is a fine tuff. As noted by Smith and others (1967, p. 12) in the Matlock area, cambering has in places occurred on the clay and is responsible for an apparent decrease in the thickness of the lava at outcrop.

Although vents are present in the area (see below) they nowhere show any evident association with the lavas, the extrusion of which is here considered to have been by eruption along fissures. This is consistent with the uniformity in thickness of the large spreads of lava.

It is usually impossible to determine the number of flows making up a lava-sheet owing to lack of exposures; most are, however, probably composite. The Upper Lava clearly shows this at Hargatewall as it contains a limestone parting in the middle. Similar features are shown by the Lower Lava in Tideswell Dale and in the Litton Dale Borehole.

Tuffs

Tuffs, though less widespread than lavas, are known at outcrop at horizons in D1 (Pindale Tuff and Dove Holes Tuff) and D2 (Litton Tuff) and possibly at two lower horizons at depth. Tuffs have also been proved in association with tuffaceous limestones in the Edale and Alport boreholes (see pp. 114, 117).

Most of the tuffs are regularly bedded though depositional form is preserved in the tuff-mound formerly exposed in Earle's Quarry, Hope, which represents a degraded cone (Eden and others 1964, pp. 76–8). Accidental blocks of limestone up to 3 ft in diameter were associated with the tuff-mound. A second mound has also been proved by boreholes at a similar horizon nearby. The Litton Tuff shows features similar to those of the Pindale Tuff, though over a larger area. At Litton it shows its greatest thickness and is locally agglomeratic, indicating proximity to a vent.

The tuffs are in general very altered, the unweathered rocks being much calcitized. They range from coarse lapilli tuffs to fine-grained water-borne rocks of mud grade. Lapilli, where present, are better preserved than the matrix; they are usually cognate but accidental lapilli of limestone are present in the Dove Holes Tuff.

The degree of sorting of the tuffs also varies. For example, drilling on the flanks of the tuff-mound in Earle's Quarry has shown that the unbedded tuff of the mound passes laterally into a well-banded tuff.

Vents are known at three localities. Though structurally intrusive these are clearly associated with explosive episodes when the tuffs were formed. The vents are filled with either fine agglomerate or lapilli tuff. The two vents in Monk's Dale (see (Figure 14)) lie on the axis of a sharp monocline and this relation is unlikely to be accidental. It is probable that deep-seated faulting is responsible for both the monoclinal fold and for the location of the two vents on it.

General stratigraphy

Shelf Province

Woo Dale Group

(Seminula (S2) Zone and basal Lower Dibunophyllum (D1) Zone)

Woo Dale Beds

The term Woo Dale Beds is introduced here for the S2 beds of the Wye valley (Cope 1933, pp. 127–30). It is synonymous with the term Daviesiella Beds' though lateral changes of facies and variations in the vertical distribution of Daviesiella render this term inappropriate. The type area thus lies to the south of the present district.

In the present district outcrops are confined to the Peak Forest Anticline (Figure 4) and to exposures farther south along Dam Dale and Hay Dale (Plate 2A). Two distinct lithofacies (see (Figure 4) and (Figure 5)) are present:

  1. The normal facies consists of thinly bedded dark grey and dark brown limestones with some bands of grey limestone and rare oolitic bands. The maximum exposed thickness of these beds is about 165 ft, at the junction of Dam Dale and Hay Dale. The lowest beds contain calcilutites at two horizons, the lower being irregularly bedded and lenticular while the upper is evenly bedded and has served locally as a lithological marker-band. The lowest beds bear Daviesiella sp. though the horizon of this brachiopod here does not correspond closely with its vertical range in the Wye valley (Cope 1939, pp. 60–2). The typical S2 brachiopods Davidsonina carbonaria and Linoproductus corrugatohemisphericus are also present. The S2–D1 zonal boundary does not correspond exactly to the lithological change at the junction of Woo Dale Beds and Chee Tor Rock. In the Dam Dale–Hay Dale section the uppermost 11.5 ft of the Woo Dale Beds bear a D1 coral fauna including Dibunophyllum bourtonense and Palaeosmilia murchisoni, while at Hernstone Lane Head this fauna occurs in the uppermost 14.5 ft.
  2. 7In the northern part of the Dam Dale–Hay Dale section Woo Dale Beds of normal facies pass laterally into a uniform group of pale crinoidal and in places shelly limestones (see (Figure 4)) which occupy the greater part of the Peak Forest inlier. These are here called the Peak Forest Limestones though they are not separately shown on the one-inch map. Though good continuous sections of these beds are lacking the total exposed thickness is of the order of 150 ft. They are of shallow-water facies and show marked sorting into bands with coarser and finer bioclastic material, mainly crinoidal; some oolitic bands have also been found. North of the outcrop, a borehole at Eldon Hill (see p. 42) is interpreted as showing 225 ft of Peak Forest Limestones with a 14-ft dolomitic band 45 ft from the base, and underlain by a probable tuff, proved to a thickness of 100 ft. At Castleton, the presence of pale crinoidal limestones of probable S2 age underground beneath D1 limestones has been noted by Ford (1952, pp. 351–2).

The development of beds of shallow-water facies in S2 near the reef-belt suggests that the Peak Forest Limestones developed as the result of a broad uplift along the edge of the Derbyshire Block which heralded the more acute and localized uplift in D1/B2 times which led to the formation of the apron-reef. S2 beds of comparable facies and in a similar position in relation to the margin of the block have been described by Sadler and Wyatt (1966, pp. 55–64) from the Hartington area. I.P.S.

The normal facies of the Woo Dale Beds ranges in the Hay Dale–Dam Dale section (see p. 40) from grey foraminiferal biocalcarenites showing a poor to moderate degree of sorting to fine micritic rocks (calcilutites) showing variations in colour and in the extent of recrystallization. The Peak Forest Limestones are coarser grained, mainly unsorted biocalcarenites and biocalcirudites, largely crinoidal but in places containing lithoclastic debris. R.K.H.

Bee Low Group

(Lower Dibunophyllum (D1) Zone)

The presence of the Lower Miller's Dale Lava to the south of a line between Dove Holes and Ox Low allows the subdivision of this group into Chee Tor Rock below the lava and Miller's Dale Beds above it. Where the lava is absent the limestones are not subdivided and are known as the Bee Low Limestones. All these limestones show a uniform lithology, when compared with both the underlying and overlying beds, being fine-grained, massive and pale. In addition, the absence of chert, with one exception, is striking in view of its abundance in the strata above. Fossils are absent or rare though they are in places abundant at restricted horizons.

Chee Tor Rock

The Chee Tor Rock consists of pale fine-grained limestones, for the most part very massive. The thickness varies from about 380 ft in the southernmost outcrops in Great Rocks Dale to about 300 ft in the north. Typically the middle and upper parts of the subdivision show the characteristic closely-spaced vertical joints noted by Cope (1933, p. 131) giving a castellated appearance to weathered sections. The lowest beds frequently stand out as strong features. The Chee Tor Rock is separately distinguished along Great Rocks Dale and Doveholes Dale, around the Peak Forest Anticline and south-east of the latter around Peter Dale.

Much of the Chee Tor Rock is relatively unfossiliferous, fossils where present being mostly restricted to well-defined bands with D1 Zone coral-brachiopod faunas or, rarely, with algal nodules. The corals present include D. bourtonense, Koninckophyllum θ, Lithostrotion junceum, L. pauciradiale and P. murchisoni. The most important faunal bands, here called the Upper Davidsonina septosa Band and the Lower D. septosa Band, lie near the top of the subdivision. The upper band, lying some 25 ft below the Lower Lava, was originally described as the "Cyrtina septosa Band" by Cope (1936, pp. 48–51) in the Wye valley section and in the present district at Buxton Bridge. Cope subsequently (1939, p. 63) noted the presence of a band with a similar fauna, some 10 to 15 ft lower in the sequence; it is uncertain whether this represents a well-developed band with D. septosa which occurs in the present district some 35 ft below the upper band and which is here referred to as the Lower D. septosa Band. The chief fossil bands in the Chee Tor Rock are indicated in (Figure 6). Despite its monotonous nature certain facts emerge from the detailed study of the stratigraphy:

  1. The lowest beds, some 40 ft thick, are usually relatively thin bedded (in 2- to 6-ft posts). A persistent coral band is present at the base on the eastern side of the Peak Forest inlier but has not been located elsewhere. It bears a typical D1 coral fauna in this area but to the north of Peak Forest appears to be represented by a band of limestone with algal nodules. As noted by Cope (1939, p. 62) bryozoa are relatively abundant both in the basal coral band and in the overlying 30 ft or so of beds.
  2. The succeeding beds, about 160 ft thick, are frequently very massive near the base. They contain a 6-ft coral band in Peter Dale and a thinner band in the Hay Dale–Dam Dale section (these bands are shown in (Figure 6) in their positions relative to the base of the Chee Tor Rock; if thinning occurs they may represent the same band). A less important coral band occurs at Wheston.
  3. The coral band of Laughman Tor, although sporadically developed, is an important horizon, being 10 ft thick at the type locality with a finely bioclastic and somewhat oolitic matrix. A band in this position has also been noted on Middle Hill (south) and near Wheston.
  4. Some 80 ft of beds, again usually very massive, separate the last horizon from that of the Lower Davidsonina septosa Band. In Duchy Quarry, Smalldale, these beds contain a well-marked algal nodule band about 1 ft thick and 40 ft from the base; this appears to be represented on Middle Hill and at Wheston by a coral band. The uppermost beds locally show crinoid debris including some stems. Some 22 ft higher in Duchy Quarry and Buxton Bridge, a thin band yields D. septosa, corals and gastropods. Locally, north of Smalldale these beds are less massive and contain fairly numerous clay wayboards, some with underlying potholed surfaces.
  5. The Lower D. septosa Band varies from 10 in to 4 ft and although sporadically developed, has been recognized over a wide area.
  6. About 35 to 40 ft of limestones with some finely crinoidal bands, separate the Lower from the Upper D. septosa Band. At Buxton Bridge these beds contain several thin clay wayboards on potholed surfaces. A thin calcilutite band is present near the top of this group of strata in Bold Venture Quarry.
  7. The Upper D. septosa Band varies from 1.5 to 5 ft. Although widespread it is locally, at Upper End, largely represented by a thick algal band with only rare D. septosa.
  8. The beds above the Upper D. septosa Band are 20 to 25 ft thick and in places very massive. Some finely crinoidal bands are present.
Lower Miller's Dale Lava

The term Lower Miller's Dale Lava is here introduced for the Lower Lava of Arnold-Bemrose (1907, pp. 246–7) to distinguish it from the Lower Matlock Lava of Smith and others (1967, pp. 8–12) which is at a higher horizon. The Lower Miller's Dale LavaThe name is here in places abbreviated to 'Lower Lava' where no ambiguity exists. occurs within the present district south-east of a line from Dove Holes to Ox Low and as an isolated patch to the north at Cave Dale. The thickness of the lava is 100 ft at Wormhill and 90 ft at Wheston but a marked northerly thinning occurs from these localities until the lava disappears.

The lava is an olivine-basalt (see also p. 120), usually very amygdaloidal and with calcite- and chlorite-filled vesicles. In places non-vesicular basalts are developed and appear to represent the central parts of flows. The lava weathers deeply and natural exposures are infrequent except in swallow-holes which commonly mark its outcrop. The Lower Lava has been penetrated in boreholes at two localities: in Great Rocks Dale a thin uppermost flow and two thicker flows below showed intervening beds of clay and tuff, the whole being 98 ft 2 in thick; the Litton Dale Borehole passed through a thick upper flow, separated from a thinner lower flow by 12 ft of limestone, the whole totalling 90 ft 6 in.

The isolated occurrence of Lower Lava at Cave Dale, Castleton, was left uncorrelated by Arnold-Bemrose (1907, p. 248) and Shirley and Horsfield (1940, p. 275) were the first to show its horizon. It is up to 25 ft thick and its outcrop extends from Hurdlow Barn to Cave Dale. To the east of the latter, drilling has shown that the lava dies out and its place is taken by the Pindale Tuff (Eden and others 1964, pp. 76–8), which stretches from the reef-belt, where it is mainly developed (see p. 61), inwards beneath the back-reef facies before dying out.

Miller's Dale Beds

The Miller's Dale Beds (see (Figure 6)) resemble the Chee Tor Rock in lithology, being pale, fine-grained and massive, and contain similar D1 faunas. Minor differences are the presence locally of limestones almost pure white in colour (a shade not usually found in the Chee Tor Rock) and the generally somewhat less massive character. Fine crinoid debris is more uniformly distributed than in the Chee Tor Rock. A few slightly oolitic bands have been noted. The thickness of the subdivision varies from 142 ft near Dove Holes to 63 ft at Wall Cliff.

The lowest beds are best seen at the north end of Wormhill Moor where they include a few inches of tuffaceous limestone resting on the Lower Lava. The succeeding 30 to 40 ft of strata are richly fossiliferous with an abundant coral fauna and brachiopods including Davidsonina septosa. In this vicinity some of these beds show a distinctly reef-like appearance with an irregular banding of possible algal origin. At Wall Cliff the reef-brachiopods Dielasma hastatum and Pugnax pugnus occur in an 8-ft bed, 32 ft above the Lower Lava. The presence of these two forms may be linked with a shallowing of the sea-floor due to irregularities in the surface of the underlying lava. These more fossiliferous strata include the equivalent of the beds with Lithostrotion aff. maccoyanum noted by Cope (1933, p. 132) immediately above the Lower Miller's Dale Lava in the Wye valley.

The higher parts of the Miller's Dale Beds call for little comment though they include the Dove Holes Tuff in the western outcrop. The tuff, about 7 ft 6 inches in thickness, lies about 50 ft above the Lower Lava and is a greenish grey clay with common limestone lapilli. Borehole sections show it to be pyritous. It rests on a strongly potholed surface.

Bee Low Limestones

In lithology and other features, such as bedding and the local presence of clay wayboards and potholed surfaces, the Bee Low Limestones, which are about 600 ft around Eldon Hill, are indistinguishable from their equivalents, the Chee Tor Rock and Miller's Dale Beds, and faunas typical of the D1 Zone are present throughout. Detailed correlation is difficult as the discovery of at least four horizons with D. septosa means that correlation of a given band is dependent on its position in relation to the top or base of the group.

Bee Low Quarry shows a 300-ft face of massive limestones, lying some 80 ft below the top of the group. Farther east, a coral band 260 ft from the base of D1 probably represents that of Laughman Tor (p. 47). At about the same horizon a 3.25-ft porcellanous band is present near Lodesbarn. Near Haddocklow the Upper and Lower D. septosa bands have been identified and a higher band with D. septosa is tentatively correlated with the Lithostrotion aff. maccoyanum horizon.

Within some 200 yd of the reef-belt the Bee Low Limestones show an increase in the content of crinoid debris and contain lenses of limestone with reef faunas which are comparable with those from the B2 apron-reef and can be correlated with limestones at about the horizon of the Upper D. septosa Band. One of these reef-faunas yielded the goniatite Bollandoceras sp. on Gautries Hill. In Eldon Hill Quarry the Upper D. septosa Band is reef-like up to 500 yd from the boundary of the apron-reef and the lower beds also contain a lens of reef-limestone. Near the reef margin the back reef (Plate 11) is locally coarsely crinoidal, with debris up to 1 in, and some bands with limestone pebbles and breccia. A 9.5-ft oolitic band is also developed north-east of Eldon Hill about 88 ft above the Upper D. septosa Band.

At Windy Knoll, back-reef limestones are well developed; they are fossiliferous with reef-brachiopods and also contain some breccia (in addition to the 'Neptunian dykes' noted on p. 110). The back-reef facies is little developed west of Treak Cliff and in The Winnats, but in Cave Dale it is better developed, the lower beds showing interdigitations of reef-limestone. Here the Lower Lava (see p. 60) is succeeded by pale limestones with a coral band, the L. aff. maccoyamum band of Shirley and Horsfield (1940, p. 275) bearing a sparse fauna of L. cf. aranea at 39 ft above the lava. A thin tuff band is present just above; this has also been proved in a borehole (Plate 4) in the adjacent Michill Bank area. Shirley and Horsfield considered that the Lower Lava was cut out in the vicinity by an unconformity but its disappearance is here (p. 60) thought to be due to the normal dying out of a flow. Local thinning of the beds between the lava and the base of D2, to about 100 ft, may be due to minor non-sequences or condensed deposition in the back-reef area and shallow-water conditions are indicated by the presence of oolite bands and local cross-bedding in the Cave Dale area.

In Pin Dale some beds of back-reef facies can be recognized but farther east their absence, at least at the present level of erosion, coincides with the general absence of apron-reef of B2–D1 age. The section here shows 82 ft of beds beneath D2 and the Pindale Tuff is calculated from boreholes (see (Plate 5)) to crop just below the exposed beds. An abnormal feature of the section is the presence of nodular chert in some abundance in the lowest 23 ft. The exceptional presence of chert in these limestones is perhaps due to a local silica concentration near the reef; Wolfenden (1959, pp. 566–8) noted the abundance of sponges in the algal reef and the silica may be attributed to this source. The higher beds show wedge-bedding and bands of breccia near the apron-reef (Eden and others 1964, p. 79). The coral band with Dibunophyllum bourtonense φ and Palaeosmilia murchisoni, noted by Jackson (1941, p. 240) and by Eden and others (1964, p. 78) as lying about 65 ft below the top of D1 is here located at 33 ft from the top, part of the difference being due to the lowering of the base of D2 in the present work (see pp. 72–3).

Pale brown to light grey limestones referred here to D1, have been proved in an underground borehole at Glebe Mine, Eyam (see p. 96). I.P.S.

The greater part of the D1 limestones consists of uniformly textured biocalcarenite. The organic content, especially that of crinoid debris, shows some variation. Foraminifera, productoid spines and rare bryozoa occur in addition to coarser bioclasts. The calcite cement shows sporadic recrystallization. The finer limestones (calcilutites) are micritic, but are seldom free from bioclastic material. Authigenic quartz occurs in small quantity in many of the limestones. A clay parting in the Chee Tor Rock (see p. 47) has been found to be a pyritic illite-mudstone with marcasite needles. R.K.H.

Monsal Dale Group

(Upper Dibunophyllum (D2) Zone)

In contrast to the rocks of the D1 Zone these beds are of very variable lithology and include dark beds. They are in addition more uniformly fossiliferous and the faunas are indicative of the D2 Zone. Both pale and dark limestones are cherty at some horizons. The presence of the Litton Tuff or the overlying Upper Girvanella Band allows these strata to be subdivided into the Lower and Upper Monsal Dale Beds. Where the Upper Miller's Dale Lava is present this is included in the group following Cope (1937, pp. 192–3). Where the lava is absent there is a sharp break at the base of the Monsal Dale Beds suggestive of a non-sequence, though the extent of this is difficult to assess.

Monsal Dale Beds beneath Upper Miller's Dale Lava

A small area of these beds, the northern continuation of the Station Quarry Beds of the Wye valley (Cope 1937, p. 180), extends into the Chapel en le Frith district. They are ill exposed at outcrop though 6.5 ft of alternating pale and dark limestones were proved below the Upper Lava in the Litton Dale Borehole. Elsewhere these beds are absent, the lava resting directly on beds of D1 age.

In Station Quarry, Miller's Dale, some 800 yd south of the sheet boundary, these beds are 25 ft in thickness and consist of thin-bedded dark grey and grey cherty limestones (Cope ibid., p. 186). The base is strongly erosive and shows a washout at one point.

Upper Miller's Dale Lava

The Upper Miller's Dale LavaThe name is here in places abbreviated to 'Upper Lava' where no ambiguity exists. is of lesser extent than the Lower in the present district, being developed only between Wormhill Moor and Old Moor (north-east of Peak Forest) and Tideswell Dale. It is similar in most respects to the Lower Lava (see p. 23) being an olivine-basalt, usually highly amygdaloidal. The maximum thickness is 100 ft at the south end of the Wormhill Moor outlier and from here the lava thins northwards, eastwards and westwards. In Tideswell Dale a very rapid north-easterly thinning takes place from the junction with Litton Dale, where the thickness is some 60 ft, to the Litton Dale Borehole only 400 yd distant where it has thinned to 8 ft. The rapid easterly disappearance of the lava in the Litton railway-cutting, on the Buxton (111) Sheet has been recorded by Cope (1937, pp. 183–4) whose description suggests a steep snout to the flow; similar conditions probably obtain at Litton Dale.

At Brook Bottom, north of Tideswell, the Upper Lava is replaced by a tuff, the Brook-Bottom Tuff of Arnold-Bemrose (1907, p. 253). At one place (see p. 62), the lava can be seen to overlie the tuff. The tuff locally contains lapilli and is interpreted as a small ash-cone at least partly surrounded and buried by lava.

Lower Monsal Dale Beds

The original term 'Monsal Dale Beds' of Hudson and Cotton (1945b, pp. 30–1) has been here extended to include the whole of the D2 succession of the Shelf Province. These beds are subdivided for descriptive purposes into a lower group of predominantly dark limestones and an upper group of predominantly pale limestones. Lithological variation of these strata is illustrated in (Plate 6). The total thickness varies from about 100 ft on Tideswell Moor to 230 ft in Cressbrook Dale, where it includes the Cressbrook Dale Lava.

The lower dark beds, usually from about 25 to 80 ft in thickness, are developed over most of the outcrop of the Lower Monsal Dale Beds. They are dark grey, usually thin-bedded and in places cherty. Some localities show paler, bioclastic bands, crinoidal or shelly; others show a bed of pale cherty limestone within the dark beds. The Lower Girvanella Band, 1 ft 9 in to 9 ft in thickness, is present at many localities near or at the base; 6 ft of dark limestone underlying the Lower Girvanella Band in Pindale Quarry is interpreted as occupying a hollow in the underlying D1 limestones. Near the reef margin 10 to 20 ft of pale-coloured coarsely bioclastic limestone ("first calcirudite" of Eden and others 1964, pp. 81–2) occur within the dark beds and extend over the whole area of Earle's Quarry; a similar section is present at Dove Holes. There is, however, in marked contrast to the B2–D1 beds, no uniform development of back-reef facies in the Monsal Dale Beds.

In the absence of the Lower Girvanella Band, Saccamminopsis sometimes occurs in the lowest few feet of the Lower Monsal Dale Beds, the two fossils appearing to be mutually exclusive. A higher horizon with Saccamminopsis is present at Dove Holes and in Earle's Quarry, some 25 ft above the base of D2; this is probably represented in the expanded sequence in Cressbrook Dale by two bands at 39 ft and 50 ft from the base respectively. At Brook Bottom what is probably the same band is well developed near the top of the dark limestones.

In the western outcrops the uppermost part of the dark beds and the lowest part of the succeeding limestones contain knoll-reefs at Dove Holes, Barmoor Clough and Sparrow Pit. The Barmoor Clough knoll has yielded fish teeth in some abundance (see p. 66). The presence of the corals Zaphrentites enniskilleni and Cyathaxonia rushiana in the dark beds at Barmoor Clough is taken as indicative of the proximity of the basin facies. The latter is further indicated by a small outcrop of P1 shale in the vicinity (see below).

In the outlier of Wormbill Moor and on the main outcrop between Whiterake and Old Moor the dark beds are ill developed, consisting only of thin dark bands in predominantly pale massive limestones with some oolitic bands. The thickness of the whole of the Monsal Dale Beds is here only some 100 ft. Near Whiterake, a clay band near the base may represent a thin tuff.

The upper pale beds vary normally from about 90 to 120 ft, an exception being the thin development noted above. These beds are mainly pale massive limestones, often crinoidal and with some shell bands. Chert is usually absent but occurs in places in the lowest beds. The most extensive development of these strata is in Cressbrook Dale where a shell bed with Gigantoproductus sp. cf. striatosulcatus semiglobosus is present 22 ft from the base and the Cressbrook Dale Lava (see below) occurs near the top. Striatifera striata occurs close to this horizon both here and elsewhere. In the Pin Dale area, Eden and others (1964, p. 85) have noted the presence of two coarse crinoidal bands (the "second calcirudite" and "third calcirudite") near the middle and at the top of the subdivision. The second calcirudite has been noted to pass laterally into flat reef in the easternmost part of Earle's Quarry. In this vicinity the presence of a local unconformity at the base of the Upper Monsal. Dale Beds results in the cutting out of some 30 ft of the uppermost Lower Monsal Dale Beds. The presence of a small knoll-reef near the top of the subdivision on Bradwell Moor is ascribed to shallowing preceding the unconformity.

The presence of knoll-reefs at the junction of this subdivision with the underlying dark beds in the western outcrops has already been noted. At Barmoor Clough a small thickness of shale at the junction of the main Edale Shales outcrop with limestones of lower D2 age has been found to contain a P1 fauna including the goniatite Girtyoceras sp. and is thus the basinal equivalent of part of the upper beds of the subdivision (see also p. 8).

The pale beds are well seen in Victory Quarry, Dove Holes, where they contain a persistent shell band, some 40 ft from their base, with Gigantoproductus dentifer and G. edelburgensis [juv].

The Cressbrook Dale Lava is an amygdaloidal basalt, up to about 20 ft thick and some 30 ft below the Litton Tuff in the northern part of the dale but dying out rapidly to the south. The lava is much more extensively developed at depth and is known over a wide area from Wardlow Mires to Great Hucklow and Middleton Dale. The greatest thickness proved is in an underground borehole in Glebe Mine (see also p. 95) near Ladywash Shaft: 208 ft of basalt, with the top some 140 ft below the horizon of the base of the Eyam Limestones. The occurrence of igneous rocks at depth north of Cressbrook Dale is illustrated in (Figure 8). It will be noted that the thickest occurrences of lava are overlain by the thinnest developments of high D2 limestone, a fact which may be due in part to the lava building up somewhat near the source, thought in the present state of knowledge, to be near the Ladywash Shaft. As interpreted, the boreholes also show a progressive upward approach of the lava towards the horizon of the Litton Tuff.

The Wardlow Mires No. 1 Borehole proved an unusual shallow-water development of oolitic and crinoidal limestones, 79 ft 5.5 in thick, between the Upper Girvanella Band and the Litton Tuff. These are interpreted as having been deposited on the flanks of a cone built up of Litton Tuff.

Litton Tuff

The Litton Tuff reaches its maximum thickness of 100 ft at Litton where it is agglomeratic with bombs up to 5 in across. Arnold-Bemrose (1907, p. 254) noted this character together with the presence of accidental bombs of fossiliferous limestone. The tuff thins away from Litton, being up to 42 ft in Cressbrook Dale, where it is poorly exposed, 10.5 ft in the Littonfields Borehole and only 2.5 ft in the Wardlow Mires No. 1 Borehole, to the north of which it is absent. At outcrop the tuff is more extensively developed, extending for over 2 miles north-west of Litton.

In the Wardlow Mires No. 1 Borehole the Litton Tuff was blue-grey and very fine-grained with gritty bands in contrast to the thick and agglomeratic nature of the tuff at Litton, which suggests a source near the latter locality. It is reasonable to picture the tuff as having formed a cone which suffered progressive burial. The effects of shallow-water sedimentation on the flanks of this cone have already been noted (see p. 28).

Upper Monsal Dale Beds

The Upper Monsal Dale Beds show a fairly uniform thickness of about 250 ft. The base is marked by the Upper Girvanella Band or in its absence by the top of the Litton Tuff. The succession in these beds (see (Plate 7)) is best shown in Middleton Dale, Cressbrook Dale, Wardlow Mires No. 1 Borehole and in Bradwell Dale. Minor erosion surfaces and clay partings occur locally and are noted in the detailed sections. The more important features are summarized below.

The beds below the Hob's House Coral Band, some 50 to 60 ft thick, are dark limestones with the Upper Girvanella Band at or near the base; the band varies from a few inches in thickness to 8.5 ft in parts of Earle's Quarry (Eden and others 1964, p. 113). The band has also been found, though thin, in pale limestones in the Hucklow Edge No. 2 Borehole. The overlying beds are of variable lithology. In the main outcrop to the north of Litton and in the Littonfields Borehole they consist of dark cherty limestones while in Cressbrook Dale there is evidence of lateral passage southwards from preponderant dark cherty limestones in the northern outcrops into pale partly bioclastic limestones with a little chert.

The Hob's House Coral Band was originally described by Cope (1933, p. 140), though apparently placed by him too low in the sequence. Shirley and Horsfield (1945, pp. 295, 298) determined the horizon of the band in terms of the Cressbrook Dale section and this work is followed here. The band, up to 5 ft thick, bears an abundant fauna with Dibunophyllum bipartitum bipartitum, Diphyphyllum sp., Lithostrotion pauciradiale and L. portlocki. In the Cressbrook Dale section clisiophylloids are less abundant than at Crossdale Head (Cope, op. cit.). In the northern part of the Cressbrook Dale section the band passes laterally northwards into a shell bed and the latter has been recognized in the Wardlow Mires No. 1 Borehole. The band has also been recognized in the Coombs Dale section (see (Plate 7)), but the Middleton Dale section fails to show it (see below).

The beds between the Hob's House Coral Band and the Black Bed, some 50 to 60 ft thick, consist of pale massive limestones showing local variation in detail. The Middleton Dale section shows a lower group of well-sorted crinoidal limestones, of evident shallow-water facies, overlain by pale massive limestones with the Lower Shell Bed ("Lower Giganteus Bed" of Morris 1929, p. 45). These beds have been described by Orme (1967, p. 27) as crinoid calcirudites and crinoid calcarenites. The Lower Shell Bed is some 6 to 7 ft in thickness and crowded with Gigantoproductus edelburgensis, the shells being often silicified. The Wardlow Mires No. 1 Borehole does not show the same development of crinoidal limestones at the base of the group and a bed of pale calcilutite is present in the lower part. The Cressbrook Dale section shows evidence of shallow-water sedimentation in the presence of bands of rolled shells and some oolitic bands at the base of the group.

The Black Bed, which consists of dark bituminous limestone, forms a useful lithological marker band in the middle of the Upper Monsal Dale Beds. It is here named in contrast to the higher White Bed of Morris (1929, pp. 47–8) and includes his Lonsdaleia Bed. The present name is preferred as the dark limestone is of wider extent than the faunal band. In Middleton Dale the bed is up to 5 ft thick and it has also been recognized in the Littonfields (see p. 69) and Wardlow Mires No. 1 boreholes. In Cressbrook Dale the Black Bed thickens to 16 ft and this increase is probably related to the basin-ward passage into dark limestones noted by Eden (1954, p. 37) in the eastern end of the Wye valley. Lonsdaleia floriformis floriformis is commonly present either just above the Black Bed (Lonsdaleia Bed of Morris), at its base or within it (Cressbrook Dale).

The beds between the Black Bed and White Bed are about 55 to 70 ft thick; they consist of pale massive limestones, mostly fine-grained and free from crinoid debris, with abundant chert in the upper one-third and sporadically developed in places below. The Middleton Dale section shows the Upper Shell Bed (Hemisphericus Bed of Morris 1929, p. 42) about 1 to 4 ft thick and with abundant Gigantoproductus crassiventer and G. dentifer ? Some 5 ft higher, Orme (1967, p. 28) has noted a thin algal band and a concentration of foraminifera in the limestones (calcarenites) overlying this. In Stoney Middleton, Orionastraea placenta, Diphyphyllum fasciculatum and other corals occur a little below the White Bed.

The White Bed is not present in Bradwell Dale but its position can be inferred; here the underlying beds are pale massive cherty limestones, crinoidal in the lower part.

The White Bed consists of buff cherty calcilutite up to 7 ft thick. Owing to its pale weathering it forms a conspicuous feature in the Middleton Dale sections where it was first named by Morris (op. cit., p. 42). Work by Orme (1967, pp. 28–9; 1970b) has shown that the White Bed is of somewhat variable texture, part being described as a calcisiltite or fine calcarenite. Insoluble residues contain small silicified gastropods, small Lingula, sponge spicules, conodonts and fish debris. The bed is attributed by Orme to very shallow-water conditions.

The beds above the White Bed, some 50 to 75 ft thick, include massive pale cherty limestones and in places some very fine-grained non-cherty beds at the top (including impersistent calcilutites). In Morris's (ibid., p. 48) Shining Tor section a massive fine-grained bed, the "Hackly Bed" is so-called on account of its fine irregular jointing. Immediately above this lies the Dibunophyllum aff. muirheadi Bed, in which D. bipartitum bipartitum and D. bipartitum konincki occur. The band is of only small lateral extent but appears to lie at the horizon of the Lonsdaleia duplicata Band, present in Furness Quarry 27 ft below the Orionastraea Band. The Orionastraea Band, some 30 to 50 ft from the top of D2, is about 2 or 3 ft thick and bears O. placenta, Lithostrotion portlocki and other corals. A higher band, with a fauna including Lonsdaleia duplicata duplicata, is present in some localities a few feet above the Orionastraea Band.

The section in Coombs Dale (see (Plate 7)) shows a general resemblance to that in Middleton Dale. However, much of the middle beds is unexposed. The Hob's House Coral Band has been recognized at the base. In the higher beds it appears likely that the White Bed has passed laterally into dark limestones.

The succession in the Hope–Bradwell Moor area (Plate 8) shows a broad correspondence to that outlined above. There is a strong development of dark cherty beds in the lower part of the sequence with the Upper Girvanella Band recognized at the base. The higher beds are pale and frequently cherty. Knoll-reefs are well developed some 30 ft above the base and these have built up in one place to join a higher reef horizon to give a complex knoll-reef some 50 ft in thickness. The L. duplicata Band is well developed in places and can be related to the Orionastraea Band, some 28 ft higher, in Intake Dale, and the band has also been noted in the Wardlow Mires No. 1 Borehole and in Cressbrook Dale. Flat-reef limestones are developed on Bradwell Moor between the horizons of these two coral bands.

In Bradwell Dale (Figure 11) all the exposed high D2 limestones, including beds down to an horizon some 75 ft below the Orionastraea Band, can be seen to pass northwards into dark cherty limestones of basin facies. Some evidence of a similar lateral passage has been noted south-east of Little Hucklow. I.P.S.

A detailed description of the petrography of the Monsal Dale Beds adjacent to the reef-belt has been given by Eden and others (1964, pp. 93–5) and a systematic description of the large range of rock types has not been attempted for the present work. The pale lithofacies consists of biocalcarenites with some lithocalcarenites and biocalcirudites. The White Bed, near the top of the subdivision, has been described (Orme 1967, pp. 28–9) as varying from a calcilutite and calcisiltite to a fine calcarenite (see p. 30). The occurrence of chert in the limestones is noted in the details; scattered authigenic quartz occurs, becoming abundant in the cherty limestones. Foraminifera vary in abundance and a concentration has been noted by Orme (ibid., p. 28) in a bed near the top of the Upper Monsal Dale Beds in Middleton Dale. The dark lithofacies consists mainly of biocalcarenites and some lithocalcarenites, some of which, as noted by Eden and others (ibid., p. 93), appear deceptively fine-grained, though some finer micritic types do occur. The dark limestones are, in general, finer grained than the pale, though some coarser bands, mainly crinoid calcirudites, are present. R.K.H.

Eyam Group

(Upper Posidonia (P2) Zone)

Eyam Limestones

The Eyam Limestones, up to about 150 ft in thickness, consist in their simplest development of dark thin-bedded cherty limestones (Plate 10). Locally knoll-reefs and flat reefs are present and the latter may constitute the whole of the subdivision. They contain a rich brachiopod fauna and, at one locality, the P2 goniatite Sudeticeras sp. Near Great Hucklow, only grey limestones are present.

The Eyam Limestones rest with a marked break on the Monsal Dale Beds. This unconformity was described by Shirley and Horsfield (1945, p. 293) though its effects have been found to be less than suggested by these authors at some localities. It seems reasonable to regard the junction as an angular unconformity in the marginal areas, where its effects can be observed, and as a non-sequence elsewhere. The junction shows in many places evidence of erosion in the presence of a potholed surface, overlain by a clay band. In Coombsdale Quarry a thin coal and seatearth are present at this horizon, providing clear evidence of emergence. At some localities, for example, near Intake Dale, knoll-reefs developed on the base of the Eyam Limestones and were apparently initiated by shallow-water conditions immediately after the pre-P2 unconformity. Some of these knoll-reefs remain as outliers. In Bradwell Dale some 40 ft of uppermost D2 strata can be seen to be cut out beneath the Eyam Limestones.

In Coombsdale Quarry the thin coal noted above is overlain by a thin shale, the "Bituminous Shale" of Morris (1929, p. 49) which has yielded the coral Cladochonus sp. Between Calver and Eyam, the Eyam Limestones show a general arrangement of dark cherty limestones with some knoll-reefs and flat reefs below and a widely developed flat reef above. At Calver Peak, a flat reef at the base of the subdivision is overlain by a smaller well-defined knoll and both show a widely developed patchy silicification probably of epigenetic origin (see p. 310). In Middleton Dale, some 35 ft of dark limestones are present at the base and a 1.5-ft coral band, the "Aulophyllum Band" of Morris (op. cit., p. 54) occurs at the junction with the overlying flat reef. Morris considered that this bed overlay the flat reef. The latter, up to 100 ft thick and widespread between Stoney Middleton and Eyam, shows the usual faunal and lithological characters of reef-limestones with, in addition, a slight development of chert in places.

In Eyam Dale, some 75 to 80 ft of predominantly dark cherty beds are present below the flat reef, corresponding to a westerly diminution of the latter, with diachronous base. The dark limestones show a bed with Gigantoproductus giganteus at 21 ft from the base and a 3-ft band 39 ft higher with Dibunophyllum bipartitum subspp. The latter has proved widespread in the Eyam–Foolow area and it is here named the Eyam Dale Coral Band. The overlying flat reef is only some 40 ft in thickness.

To the west of Eyam Dale the flat reef dies out and lateral passage of all but the lowest part of the dark cherty limestones into grey bioclastic limestones takes place. These beds present a more normal shelf facies than the basinal dark beds in the Eyam Limestones and the area in which they are developed is that lying farthest into the shelf area. These beds contain a series of eleven knoll-reefs in their upper part, those in the Grindlow–Foolow area showing a marked elongation parallel to the limestone-shale junction. Lower in the succession a knoll at the junction with beds of the dark lithofacies is well seen in Linen Dale where it was first noted by Morris (1929, p. 52). A bed with Gigantoproductus edelburgensis and G. sp. cf. gigantoides passes laterally into the knoll. The nearby section in the sink-hole near Waterfall Farm shows the Eyam Dale Coral Band.

The Wardlow Mires boreholes proved some 30 ft of dark thin-bedded cherty limestones overlain unconformably by P2 shale (see below). Mudstone partings were a frequent feature of these limestones, especially in their upper part. Abundant Lingula and sporadic Orbiculoidea and trilobites occurred, especially in the mudstone partings. Inarticulate brachiopods have not been recorded from surface exposures. As elsewhere an erosive base with a mudstone parting is present.

To the south of Great Hucklow the grey lithofacies noted above extends to the base of the Eyam Limestones. To the north-west of the village, however, lateral passage into dark beds again occurs and the grey beds appear to wedge out in the middle of the subdivision. The presence of these dark beds was noted by Shirley and Horsfield (1940), pp. 286, 288) in Jenning's Dale and the fauna compared to that of the dark beds of Cawdor Quarry, subsequently described (Shirley 1959, pp. 414–5) under the name Cawdor Limestones, which contain the P2 fossil Goniatites granosus. Shirley and Horsfield also noted the presence of a large knoll-reef in these beds north of Nether Water Farm; this is here considered to have been formed by the junction of two knolls.

In Bradwell Dale a large flat reef forms the whole of the Eyam Limestones. Sections at the south end of the dale show two phases of lateral growth on the margin, an initial stage of restricted spread and a later stage of more vigorous spread. Lateral passage into dark cherty limestones is here well marked. The flat reef reaches a maximum thickness of about 130 ft and the uppermost beds are very coarsely crinoidal in places with debris up to an inch in diameter.

Isolated occurrences of beds referred to the Eyam Limestones in the shelf area are also present in the northern and western outcrops. In Windy Knoll Quarry, they occur as dark fillings to Neptunian dykes in pale massive D, limestones of back-reef facies. Near Perryfoot, a small outlier of dark limestone is present, resting on D1 back reef. Both these are referred to P2 in view of the presence of the goniatite Sudeticeras sp. in similar limestones near Peakshill (see p. 111).

In the westernmost part of the limestone area, the Eyam Limestones are present in a narrow outcrop around Brook House. (Figure 7) shows the relation of this to the Miller's Dale Beds on which they rest with large unconformity, and to the D2 limestones which occupy a similar geographical position farther north. The P2 and D2 outcrops are separated by a fault of general easterly trend and the diagram demonstrates the pre-P2 age of this structure.

The greater part of the Brook House outcrop consists of dark cherty limestones some 30 ft thick. The uppermost beds contain an abundant coral fauna in several bands within 14 ft of strata, some or all of which may represent the Eyam Dale Coral Band. Near Brook House, a flat reef some 30 ft thick occurs at the base and it is on the presence in this of Sudeticeras sp., together with the brachiopod fauna, that the dating of these beds depends. Some 16 ft of grey and dark grey limestones overlie the flat reef. T.P.S.

Little petrographical work has been done on the Eyam Limestones, which typically resemble the dark limestones in the Monsal Dale Beds. In Eyam Dale they are dark biocalcarenites, biomicrites and biocalcirudite-biocalcarenites, and intergranular hydrocarbon occurs sporadically. R.K.H.

Shales of P2 age

On the shelf, shales of P2 age are known only from the Wardlow Mires outlier. Here some 11 ft of shales have been proved in the Wardlow Mires Nos. 1 and 2 boreholes. No. 1 Borehole yielded Sudeticeras cf. stolbergi at 80 ft 1 in. The base of the shales is unconformable and in the southern part of the outlier they rest on D2 limestones. At Wardlow Mires itself the shales rest on the lower dark beds of the Eyam Limestones, while west of Castlegate they overlie the higher grey lithofacies. There is no evidence of an unconformable junction with the Namurian.

Marginal Province

The beds present in this province at surface in the northernmost Viséan outcrop in the district include the reef-complex of the Castleton area and a thin development of overlying strata. The lateral development of the reef-complex is to some extent masked by the unconformable base of the Namurian.

Apron-reef

The apron-reef is present nearly continuously from near Sparrow Pit to the vicinity of Bradwell (Plate 11). The lithology and sedimentation have been described on pp. 16–9.

The apron-reef as described here includes the Castleton Limestones (B2) and part of the Nunlow Limestones (P1) of Shirley and Horsfield (1940). The poorly bedded character of the apron-reef limestones makes detailed stratigraphy and correlation difficult to establish, but the general faunal succession is as follows:

The faunas, which are rich in brachiopods, gastropods and bivalves and contain occasional goniatites, are further discussed on p. 140. Beds of high B2 age are of widespread occurrence while low B2 and P1 beds are discontinuous and restricted in general to the inner and outer margins respectively of the apron.

The lateral passage of the apron-reef into beds of shelf facies has already been described (p. 18). At the ends of the reef-belt the apron appears to thin and in these areas it can be seen to overlie beds of shelf facies; this is readily interpreted if the lateral passage is considered as taking place partly by interdigitation.

The B2 apron-reef is in general massive and poorly bedded while the P1 reef is more regularly and evenly bedded. Parkinson (1965, p. 164) considers on faunal grounds that a non-sequence of some importance is present between upper and lower B2. This cannot be considered firmly established though a break in about the right position is present near the Blue John Mine. Intra-B2 movements have been invoked during the present work to account for the off-setting of the reef-belt and production of a knoll-like mass of reef-limestone at Middle Hill.

To the east of Pin Dale, apron-reef of B2 age is in general absent at outcrop and it has been suggested (see p. 13) that this is most probably due to penecontemporaneous movement along the line of Dirtlow Rake. Small inliers at the base of Nunlow Quarry and at the extreme eastern end of the reef-belt are, however, of B2 age.

At Jack Bank, reef-limestones of P1b age rest unconformably on D1 shelf limestones with the Pindale Tuff (see p. 108). Strata of P1a age are present locally, probably as a channel-fill (Eden and others 1964, p. 90) in the upper surface of D1. Steep inward dips at the top of the frontal slope of the apron-reef have led the above authors to infer the presence of a P1b knoll, now largely eroded away, at Upper Jack Bank.

Beach Beds

The Beach Beds form a restricted outcrop in a curve in the frontal slope of the apron-reef and at its foot on the west side of Castleton (see (Plate 11)). They consist for the most part of rounded shell debris with some finer-grained grey beds, grey crinoidal bands and dark bituminous bands of basinal type. A detailed description has been given by Sadler (1964) who concluded that they represented a fan-like deposit at the foot of a channel coinciding approximately with the present-day Winnats gorge. The Beach Beds were considered to be contemporaneous with the adjacent apron-reef and of B2 age.

The above interpretation is not favoured in the present account for the following reasons. The Castleton Borehole (see below) proved the presence of a coral band with a fauna of high D2 age (see p. 111) associated with beds of Beach Beds type. These beds are considered to fall within the P2 of the fully developed basin succession. A widespread unconformity is known to be present in many places, for example at Bradwell, near the margin of the limestone outcrop at the base of the Eyam Limestones and close to the base of P2 (see (Figure 3)). If the source of supply lay, as postulated by Sadler, in the back-reef area, it is difficult to account for the abundance of shell debris, as the back-reef is not very fossiliferous behind Treak Cliff. The interdigitation of reef-like limestones within the Beach Beds can be disregarded as proof of their association with the B2 apron in view of the widespread occurrence of flat reef in P2.

The Beach Beds, therefore, are regarded as of probable P2 age though it is possible that they were formed somewhat earlier than the main transgression of the Eyam Limestones.

Dark limestones overlying the apron-reef

A small thickness of dark limestones is present above the apron-reef in Castleton village. This has failed to yield diagnostic fossils. However, between Pin Dale and Castleton, Parkinson (1947, p. 112) obtained the P1b fossil Goniatites cf. spirifer Roemer from a dark limestone at the foot of the frontal slope of the apron and perhaps the basinal equivalent of the highest beds of the apron-reef. Near Peakshill (see p. 111) a few inches of dark limestone, resting on B2 apron-reef, have yielded the P2 goniatite Sudeticeras sp.

P2 Shale

Shales of P2 age apparently crop out in a small area east and south-east of Treak Cliff, Castleton. The outcrop, obscured by head, has been calculated from the record of the Castleton Borehole (see below). In the Hope Cement Works Borehole a small thickness of Viséan shales underlies the lowest Namurian; these beds, however, occur at a greater depth than in the Castleton Borehole and have been interpreted as being cut out by unconformable overlap at outcrop.

Vulcanicity

Vulcanicity in the marginal province resulted in the formation of the Speedwell Vent (see pp. 300–1) from which, however, the surface deposits appear to have been eroded, leaving only the neck. A small thickness of tuff is present in dark post-reef limestones at Castleton, though its source is uncertain. The Pindale Tuff, associated with the tuff-cones in the back-reef area (see pp. 61–2) extends outwards beneath the apron north of Pin Dale and is overlain unconformably by Namurian shales. The Hope Cement Works Borehole proved 149 ft 6 in of pillow lavas with some tuff and a tuffaceous limestone beneath 53 ft of grey to dark grey thin-bedded limestones with Lonsdaleia duplicata at the top. The lavas (see also p. 113) are attributed to a local eruptive centre on the line of the reef-belt, perhaps governed by the same deep-seated fracture.

Basin Province

Beds of the basin province are concealed by the Namurian and are known mainly from the Edale (Hudson and Cotton 1945b, pp. 1–35) and Alport (Hudson and Cotton 1945a, pp. 256–95) boreholes (Figure 3). The succession in these is summarized on pp. 113–9.

Seminula (S2) Zone.

Beds of this zone are known only from the Alport Borehole where 528 ft were proved. They varied from grey to dark grey limestones with beds of calcilutite and breccia in places. The presence of chert at several levels contrasts with its absence in the shelf area and finds a parallel in the Permian of the Guadalupe Mountains area, Texas (see Newell and others 1953, pp. 161–2). The faunal affinities are with the shelf area with a coral-brachiopod fauna including Davidsonina carbonaria.

Lower Dibunophyllum (D1) Zone.

Beds of this zone, 326 ft thick in the Alport Borehole, consist of grey and grey-brown limestones with some shale partings in their upper part and some chert throughout. These beds bear a D1 coral-brachiopod fauna in the lower part while Goniatites sp. ?maximus group was present within the uppermost 59 ft of beds. The uppermost part of the zone is represented by B2 strata (see below). In the Edale Borehole there is no B2 and the D1 Zone is represented by the lowest 77 ft of beds proved: dark grey-brown limestones with a calcilutite band. The fauna of these beds was not diagnostic and their correlation depends on the presence of the Lower Girvanella Band at the base of the succeeding strata.

Upper Beyrichoceras (B2) Zone.

Beds of this zone are present in the Alport Borehole only and consist of 52 ft of mudstone above and 159 ft of limestone, partly thin-bedded or tuffaceous with shale partings, below. Both bear goniatites including Beyrichoceras cf. delicatum, Goniatites aff. hudsoni and G. struppus.

Upper Dibunophyllum (D2) Zone.

Beds of this zone are present only in the Edale Borehole as 63 ft of limestones, pale grey with some tuff debris above and dark below, with Girvanella in the lowest 10 ft. In the Alport Borehole these strata are represented by beds assigned to P1 (see below).

Lower Posidonia (P1).

In the Alport Borehole these beds, 294 ft thick, are represented by:

(a) Grey and grey-brown limestones, tuffaceous and with tuff bands in their lower part and with a 50-ft mudstone at 56 ft from the base, 153 ft. The fauna includes G. crenistria (P1a Zone). The thinner development in the Edale Borehole, 198 ft, also shows mudstones, including some limestones, above and a tuffaceous limestone at the base.

(b) Mudstones with some thin limestones representing the Goniatites falcatus (P1b), G. spaericostriatus (P1c) and G. koboldi (P1a) zones, 141 ft.

Upper Posidonia (P2).

In the Alport Borehole this consists of 97 ft of beds, mainly mudstone but with 10 ft of pebbly limestone and breccia at the base. Three zones are present: Mesoglyphioceras granosum (P2a), Neoglyphioceras subcirculare (P2b) and Lyrogoniatites georgiensis (P2c). In addition to goniatites, Caneyella mernbranacea is abundant in the mudstones. The Edale Borehole shows 94 ft of P2 strata with 47 ft of grey and dark grey limestones at the base.

Variations in the basin province

A comparison of the sections of the two bore-holes allows certain conclusions to be drawn regarding variation in the basin area. The lowest beds represent an imperfectly developed basin facies and the faunas recall those of the shelf area, resulting in the use of the coral-brachiopod scheme for zonation. Basin faunas appear first (B2) in the Alport Borehole, farthest away from the shelf area and this also shows a thicker succession than in the Edale Borehole, which is relatively close to the shelf. Another basinal characteristic, the development of thick mudstone, instead of limestones, also occurred earlier (B2) in the Alport than in the Edale Borehole, and where limestones are present at higher levels they tend to be thinner at Alport than at Edale. These facts point to a gradual spread of true basinal conditions outwards towards the shelf from the Alport area, the conclusion of the process being their encroachment on to the shelf area during the formation of the Eyam Limestones.

Details

Shelf Province

Woo Dale Group (S2 and basal D1)

Woo Dale Beds

The main outcrop of the Woo Dale Beds lies in the axial area of the Peak Forest Anticline (Figure 4), (Figure 5). Associated small faulted inliers are present in the valley of Dam Dale and Hay DaleDam Dale, Hay Dale, Peter Dale and Monks Dale are parts of the same valley., south of Peak Forest.

Dale Head to Hernstone Lane Head

The valley (Cope 1933, p. 127). The sectionSections from which faunas have been obtained bear a locality number (see also Appendix 2) and each individual item is distinguished by a small letter. These letters do not imply any correlation between sections. Where necessary, sections are divided between different strati-graphical headings. Woo Dale Beds in this area show lithological (loc. 1) in the main dale at Dale Head characters closely comparable with those of [SK 1234 7662] shows: the S2 beds of the type section in the Wye

feet

Chee Tor Rock (see p. 49)

(e) Limestone, medium grey finegrained; crinoid debris, corals and brachiopods including Linoproductus sp. hemisphaericus group

10

(d) Limestone, dark fine-grained slightly bituminous

about 3

(c) Limestone, pale to medium grey

3

(b) Limestone, dark slightly bituminous fine-grained; scattered crinoid columnals

3

(a) Limestone, grey-brown thin-bedded fine-grained; band 20 ft from base with Lithostrotion martini, Dielasma hastatum, Linoproductus corrugatohemisphericus, Megachonetes sp. papilionaceus group

24

The fauna of bed (a) is indicative of the S2 Zone. However, the section in the tributary dale at Dale Head (see below), unfortunately separated from this section by faulting, shows a definite D1 fauna in a nearly similar position with regard to the base of the Chee Tor Rock. All the beds (b) to (e) in this section are accordingly referred to D1.

The section (loc. 2) in the eastern tributary dale at Dale Head [SK 1248 7653] is more complete than that given above:

feet

Chee Tor Rock (see p. 49)

Beds ill-exposed (e);small exposures of dark limestone at 2 ft from base with brachiopods and L. martini

18.5

Limestone, dark to medium grey-brown, finely crystalline, well-bedded in beds up to 2 ft thick; a little crinoid debris, slightly paler and more massive in lowest 12 ft; fauna, at 1.25 to 3.75 ft from top (d)Dibunophyllum bourtonense φ, Lithostrotion martini, L. pauciradiale, Palaeosmilia murchisoni, Athyris expansa, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group; at 17 ft from top (c) Lithostrotion cf. aranea, L. martini, L. pauciradiale, Linoproductus cf. corrugatus; at 29 ft from top (b) colony of Syringopora cf. geniculata; at 38 ft from top (a) P. murchisoni, Monograptus sp. papilionaceus group

44

The incoming of P. murchisoni in the lowest faunal band is taken to mark the base of the D1 Zone.

The inlier of Dale Head is faulted off on the northern side, but a further small faulted inlier is present 0.25 mile N.N.W. of Dale Head near the main S2 outcrop. Exposures here are scanty though a few feet of dark limestone are exposed by a small working for calcite [SK 1200 7694] on the west side of the valley.

At the southern end of the main outcrop the section (loc. 3) at the junction of Dam Dale and Hay Dale [SK 1187 7781] (Plate 2A) provides the best sequence of the Woo Dale Reds in the area:

feet

Chee Tor Rock (see p. 50)

(p) Limestone, dark grey fine-grained; D. bourtonense φ, Lithostrotion martini, L. pauciradiale, L. cf. sociale, A. cf. expansa

3.5

(o) Not exposed

3

(n) Limestone, medium brown to grey finely crystalline to fine-grained in beds 2 to 3 ft; top 5 ft with D. bourtonense p, Koninckophyllum θ Vaughan (1905, p1. 23, fig. 4), L. martini, L. pauciradiale (base of D1); at 5 ft from base, band with L. aff. martini, Monograptus sp. papilionaceus group [these beds form a prominent cliff]

32

(m) Not exposed

15

(l) Limestone, medium to dark grey-brown, in beds 0.5 to 1.5 ft; lowest 10 ft with Lithostrotion arachnoideum, L. martini, bryozoa, brachiopods including Semiplanus sp. nov.

24

(k) Limestone, pale grey finely crystalline, in beds up to 1.25 ft

about 7

(j) Not exposed

12

(i) Limestone, grey-brown very finely granular, oolitic in places; L. martini, Linoproductus cf. corrugatus, L. sp. hemisphaericus group

15

(h) Calcilutite, brown white-weathering, sharp top and base (this is the lithological marker horizon of (Figure 4))

3.5

(g) Limestone, medium grey fine-grained

2

(f) Limestone, off-white fine-grained with a little fine crinoid debris; top 7 ft more massive with sporadic corals, including Lithostrotion cf. sociale and indeterminate gastropods; thin-bedded below, with bryozoa, A. expansa, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group, Semiplanus sp. nov

10.5

(e) Calcilutite, grey to pale grey poorly bedded; band at 9 ft from base with L. sp. hemisphaericus group

13.5

(d) Limestone, dark grey fine-grained in beds up to 2 ft; band at 3 ft from base with Daviesiella sp., Linoproductus sp.

5.5

(c) Calcilutite; upper 3 ft dark, in 3 beds; lower part brown and irregularly bedded; Carcinophyllum vaughani, Davidsonina carbonaria, Daviesiella sp., L. corrugatohemisphericus, L. sp. hemisphaericus group

5.5

(b) Limestone, pale brown fine-grained, somewhat oolitic, shelly in top 10 in and at base; brachiopods including Monograptus sp. papilionaceus group

10

(a) Calcilutite, brown; brachiopods including L. aff. corrugatohemisphericus, L. cf. corrugatus, L. sp. hemisphaericus group, Monograptus sp. papilionaceus group

3

Traced laterally, the calcilutites of the lower part of the section (though not the 'marker horizon') are found to be very irregular and lenticular in character, swelling out and thinning rapidly. It should also be noted that the horizon of the beds with Daviesiella in this section differs substantially from that found by Cope (1939, pp. 61–2) in the Wye valley. The present section yielded Daviesiella only between a level 130 ft below the base of the Chee Tor Rock and the lowest beds exposed some 23 ft below.

The most northerly section (loc. 4) attributable to the normal facies of the Woo Dale Beds is at Hernstone Lane Head [SK 1220 7876]:

feet

Chee Tor Rock (see p. 50).

(d) Limestone, dark; corals in upper 5.25 ft, thin-bedded and shelly below; Dibunophyllum sp., Lithostrotion junceum, L. pauciradiale, L. cf. sociale, P. murchisoni, bryozoa, brachiopods including productoids, Monograptus sp. papilionaceus group

11.25

(c) Limestone, dark grey fine-fine-grained; L. martini, P. murchisoni, bryozoa, Dielasma hastatum, M. sp. papilionaceus group, Streptorhynchus senilis (base of D1 Zone)

3.25

(b) Not exposed

4

(a) Limestone, pale grey, massive in lowest 6 ft; C. vaughani, L. martini, M. sp. papilionaceus group

15.5

Peak Forest

The Peak Forest Limestones present a facies distinct from that already described, being pale, more massive and crinoidal. They show less contrast in lithology to the overlying Chee Tor Rock than the normal Woo Dale Beds but are still quite distinct. The lateral passage between the two facies takes place quite sharply along a north-north-easterly line running from near Hernstone Lane Head through a point a little north of the large section in Dam Dale described above. The relationships of the two facies are made clear when the calcilutite marker band noted in the Dam Dale section is traced northwards into the outcrop of the Peak Forest Limestones. (Figure 4) shows the positions of the outcrops of the two facies and of the calcilutite marker. The lateral passage appears to occur at a higher horizon at Hemstone Lane Head than in Dam Dale.

The Peak Forest Limestones are well exposed on the west side of Dam Dale [SK 1173 7845]: rather dark grey fine-grained limestone 5.5 ft, on 24 ft of grey-brown fine-grained limestone in posts up to 3 ft thick, with some very crinoidal bands and some productoids. On the opposite side of the valley the most northerly exposure showing the calcilutite marker band is seen [SK 1194 7846] 210 yd E. of the last exposure: pale grey limestone 4 in, calcilutite 1 ft 6 in, on fine-grained pale grey limestone 1 ft 2 in. An exposure (loc. 5) [SK 1170 7809] east of Loosehill Farm showed 2 ft 6 in of pale brown finely granular slightly crinoidal limestone with brachiopods including Monograptus sp. papilionaceus group, smooth spiriferoids and orthotetoids.

Around Peak Forest village the Peak Forest Limestones occur as an outlier forming part of the roof of a large dolerite sill (see p. 295). An exposure (loc. 6) [SK 1198 7928] showed 6 ft of buff crinoidal and oolitic limestone with Koninckopora inflata, Linoproductus cf. corrugatohemisphericus, L. cf. corrugatus and Monograptus sp. papilionaceus group. A small exposure (loc. 7) [SK 1202 7946] yielded Lithostrotion martini [close to the S2 form of the species]. Partly altered beds overlying the dolerite are seen in another section [SK 1163 7877] near Damside Farm:

feet

Dolomite, brown saccharoidal, with calcite veins

about 4

Not exposed (except for 6 in of dark brown fine-grained limestone in middle)

6

Limestone, pale grey-brown finely crinoidal, with a 9 in by 5 ft irregular dark silicified patch

7

Limestone, dark brown finely crystalline, with some fine crinoid debris

6

Limestone, grey-white fine-grained slightly marmorized, with some crinoid columnals and fine shell debris; chert in irregular masses up to 1 ft, bedding rather irregular

4

Limestone, grey to grey-white marmorized with dark chert in lenses up to 2 in by 10 in and irregular masses up to 3 ft 3 in; some silicified crinoid columnals; calcite in a 2-in pocket at top, bedding irregular, expanding around chert masses

11.5

Not exposed about

5

Dolerite, hard dark

5.5

In view of the general absence of dolomites in the Peak Forest Limestones, the dolomite in the above section is considered to be secondary. This and the other features of this section due to alteration by the dolerite are discussed on p. 295.

To the north-west of Peak Forest a quarry [SK 1090 7952] near Chamber Farm shows a 21-ft section of the Peak Forest Limestones, finely granular pale grey-brown, rather massive and with very crinoidal bands. Some 0.5 mile to the north-west these beds have been dug in the past in a series of small workings for lime-burning in and around Hartle Plantation. A typical exposure [SK 1053 7992] shows 4 ft of off-white shelly bioclastic and oolitic limestone, and another [SK 1055 7999] nearby shows 12 ft of off-white granular crinoidal shelly limestone. A quarry (loc. 8) to the north of Hartle Plantation [SK 1040 8020] shows beds near the top of the Peak Forest Limestones:

feet

(d) Limestone, pale grey crinoidal, with some coarser bands

11

(c) Limestone, pale grey oolitic and finely crinoidal

2.5

(b) Limestone, pale grey; C. vaughani, Lithostrotion martini, L. aff. portlocki, bryozoa, Linoproductus corrugatohemisphericus, L. sp. hemisphaericus group, Monograptus sp. papilionaceus group

1

(a) Limestone, pale grey-brown, with very crinoidal bands

7

The fauna is indicative of the S2 Zone, the top of the Peak Forest Limestones corresponding to the S2/D1 boundary.

Exposures in Perry Dale show beds near the top of the Peak Forest Limestones, closely overlain by the Bee Low Limestones, though the actual junction is not exposed. A section (loc. 9) [SK 1071 8069] of the uppermost exposed Peak Forest Limestones is as follows: off-white thin-bedded limestone with L. sp. hemisphaericus group and Monograptus sp. papilionaceus group 1 ft, on pale grey to brown well-bedded finely crinoidal limestone with more coarsely crinoidal bands 12 ft. The fauna, though not diagnostic, is probably S2.

A section [SK 1078 8025] in an old quarry south of Nether Barn shows beds lower in the Peak Forest Limestones than those described in preceding sections: pale brown well-bedded crinoidal limestone 21 ft.

On the north-eastern side of the outcrop a section in Conies Dale (loc. 10) [SK 1201 8019] lies at or near the junction of the Peak Forest Limestones and the Bee Low Limestones: finely crinoidal limestone a few inches, on pale brown fine-grained limestone with Lithostrotion martini, bryozoa and Linoproductus sp. ?hemisphaericus group 1 ft 9 in. Between this locality and Conies Farm the underlying limestones, pale brown and crinoidal, are exposed.

Eldon Hill and Castleton

A borehole at Eldon Hill QuarryInformation from driller's log and from examination of cutting-samples by Dr. D. C. Knill. The samples were loaned by Messrs. Eldon Hill Quarries Limited. [SK 1128 8156], after passing through about 280 ft of beds referred to the Bee Low Limestones (see p. 58), entered a series of predominantly grey and pale grey crinoidal limestones. The only major lithological variations in these beds were the presence of grey non-crinoidal limestones between about 405 ft and 427 ft and of grey fine-grained limestones with a little dolomite between about 446 ft and 460 ft. From 505 ft to the bottom of the borehole at 605 ft feldspar, clay minerals and abundant iron oxides occurred in the samples indicating the presence of igneous rock; this is tentatively interpreted as a tuff. Tuffs in a similar geographical relation to the reef-belt (see p. 61), though at a higher horizon, have been described by Eden and others (1964, pp. 76–8).

At Castleton, the presence underground of limestone "indistinguishable from S2 limestones of Peak Forest" was recognized by Ford (1952, pp. 351–2) in the Speedwell Mine. These limestones were met in the Speedwell Level (the main crosscut) between its intersection with Faucet Rake at the 'Bottomless Pit' [SK 1400 8235] and its furthermost point [SK 1395 8215]. Ford records a 2-in bed of clay "at the end of the artificial level". The height of the level is given as 742 ft O.D. and the horizon of the surface here, at about 1260 ft O.D., is a few feet above that of the Lower Lava. Assuming an average thickness of about 300 ft for the Chee Tor Rock, the clay parting must lie some 200 ft below the top of S2 and therefore at or close to the horizon of the igneous rock met with in the Eldon Hill Quarry Borehole.

In Peak Cavern, Castleton, Ford noted "rather dark crystalline limestone" in the entrance, overlain by pale calcite-mudstone of D1 age. The lowest beds here were also referred by Ford to the S2 Zone and they become pale and crinoidal when traced into the inner part of the cave beneath the upper end of Cave Dale, only 0.25 mile S.E. of the end of the Speedwell Level.

Bee Low Group (D1): southern area

Chee Tor Rock
Great Rocks Dale

Extensive quarrying of the Chee Tor Rock has provided excellent sections, particularly in the upper third of the subdivision; the more important of these are quoted below.

On the southern margin of the district all but the uppermost few feet of the Chee Tor Rock is exposed in the inaccessible face of Tunstead Quarry [SK 096 743]. The total thickness is about 380 ft. A generalized sectionSupplied by Mr. P. F. Dagger with permission of Imperial Chemical Industries Limited. of the uppermost beds, those falling within the present district, is as follows:

feet

inches

Limestone (large Davidsonina septosaFossil names in unnumbered surface sections refer to field identifications.at top)

40

0

Clay, on potholed surface

10

Limestone

35

0

Potholed surface

Limestone

6

0

Clay

6

Limestone

34

0

Clay

3

Limestone

6

0

Potholed surface

Limestone, very thick-bedded

70

0

The lowest beds are about 180 ft above the base of the Chee Tor Rock and the highest near the horizon of the Upper D. septosa Band. The very massive character of the lowest beds in the section is a particularly striking feature.

At the "north end of Tunstead Quarry", about 35 ft and 50 ft respectively below the top of the Chee Tor Rock, Cope (1939, pp. 61–2) recorded potholed surfaces beneath clay partings. The potholes were from 3 to 4 ft in diameter and 2 to 3 ft in depth. The possible origin of these features, which have been found during the present work to be more extensive both laterally and in horizon, is discussed on p. 17.

To the north of Tunstead Quarry most of the sections in the Chee Tor Rock have now been obscured by tipping. Faulting has resulted in the preservation of several patches of Lower Lava in this area (see p. 52). A section [SK 1004 7493], near the railway and starting below the lava, is as follows:

feet

Clay, weathered Lower Lava

Limestone, top with potholes up to 1 ft deep; top 10 ft strongly marmorized; a 1.5-in clay parting at 9.25 ft from top

26

The exceptional extent of the marmorization at this locality is difficult to explain, particularly as the overlying rock is a lava. About 0.25 mile to the north of this locality the Upper D. septosa Band, 2 ft thick, is exposed [SK 0990 7532] in a railway-cutting. The same band is better developed (loc. 11) [SK 1011 7512] near Great Rocks Lees as a 4-ft band with Koninckopora sp. and gastropods.

The old quarry [SK 0980 7576] at Buxton Bridge shows a good section of the Chee Tor Rock, commencing about 12 ft below the top:

feet

inches

Limestone, pale fine-grained somewhat crinoidal; scattered fossils

12

0

Upper D. septosa Band: lithology as below; D. septosa and productoids

2

6

Limestone, near white fine-grained; scattered fossils

9

0

Clay parting, orange and white up to 3 ft thick on north side of quarry, 6 in on south, on erosion surface with potholes up to 21 in deep average

1

9

Limestone, pale fine-grained; scattered corals

5

3

Clay parting on slightly eroded surface

0 in to 2

Limestone, as above; scattered fossils include ?D. septosa fragments and a gastropod

4

10

Clay parting, on slightly potholed surface

0 in to 3

Limestone, massive fine-grained, with some crinoid debris; productoids at 5 ft from base; gastropods in a 6-in band at 13 ft from base

15

0

Clay parting, on slightly potholed surface

0 in to 1

Limestone, pale massive fine-grained; scattered productoids near top

4

0

Lower D. septosa Band: lithology as above; algae and D. septosa

1

6

Limestone, as above

4

0

At Peak Dale, Duchy Quarry (loc. 12) [SK 0938 7681] (Plate 3A) 280 yd E. of Peak Forest Station the following section is shown immediately underlying the Lower Lava:

feet

inches

(p) Limestone, pale fine-grained

8

0

(o) Limestone, as above, locally crinoidal

4

0

(n) Limestone, as above, with corals and scattered brachiopods

11

6

(m) Upper D. septosa Band: limestone as above; D. septosa, Gigantoproductus sp., Linoproductus sp.

1

6

(1) Limestone, pale fine-grained, sparsely crinoidal in top 14 ft, finely crinoidal below with rare brachiopods

28

0

(k) Limestone, some crinoid debris in upper part (part coarse); algae, D. septosa and a few productoids

5

2

(j) Lower D. septosa Band; pale fine-grained limestone with Chaetetes depressus, Dibunophyllum bourtonense, Lithostrotion martini, P. murchisoni, Syringopora spp., Davidsonina septosa, Delepinea comoides, Gigantoproductus sp. edelburgensis group, Monograptus sp. papilionaceus group

10

(i) Limestone, pale rather crinoidal, with coarsely crinoidal lenses; a few Davidsonina septosa and productoids

8

0

(h) Parting; brown clay on potholed surface (with potholes up to 9 in deep)

1 in to 10

(g) Limestone, pale grey to off-white with stylolite band up to 9 in at base; rare corals and productoids; marked irregular bedding plane at base

10

9

(f) Limestone, pale grey fine-grained; L. martini, P. murchisoni and Delepinea sp.

2

3

(e) Limestone, pale grey to off-white fine-grained; rare corals and productoids

20

0

(d) Limestone, pale fine-grained algal; 'Girvanella'nodules encrusting shell fragments, C. depressus, Davidsonina septosa [with algal coating, rare]

1

0

(c) Limestone, pale fine-grained

6

6

(b) Not exposed

1 ft to 2

0

(a) Potholed surface on quarry floor, with potholes up to 7 in beneath quarry floor

On the west side of Great Rocks Dale the section in Bold Venture Quarry [SK 0890 7655] is closely similar to that in Duchy Quarry but does not extend down so far, showing the uppermost 58 ft of the Chee Tor Rock, the top of the section being close to the horizon of the base of the Lower Lava. The section differs from that in Duchy Quarry mainly in the local development of a band of pale calcilutite 1 to 1.25 ft thick and 6.5 ft below the Upper D. septosa Band.

Over half a mile west of the last section, Upperend Quarry (loc. 13) [SK 0833 7707] also shows the uppermost part of the Chee Tor Rock, the highest beds lying 2 to 3 ft below the Lower Lava:

feet

inches

(t) Limestone, off-white fine-grained

5

0

(s) Limestone; algal nodules encrusting shell fragments, K. inflata, P. murchisoni ?, D. septosa, D. septosa transversa, G. edelburgensis, Linoproductus sp. hemisphaericus group, Megachonetes sp., smooth spiriferoids

1

0

(r) Limestone, white fine-grained; sporadic brachiopods including D. septosa, a few large crinoid columnals

5

6

(q) Parting of yellow clay

3

(p) Limestone, pale fine-grained, slightly crinoidal

7

0

(o) Upper D. septosa Band: limestone as above; algae [enclosing shell fragments], Dibunophyllum bourtonense φ, Lithostrotion martini, S. cf. geniculata, bryozoa, Davidsonina septosa, D. septosa transversa, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group, smooth spiriferoids, Bellerophon costatus, Straparollus sp. (fauna mainly in top 1.5 ft and bottom 2 ft)

5

0

(n) Limestone, pale fine-grained, slightly crinoidal; scattered corals and brachiopods; clay parting 0 to 3 in at 8 ft from base; stylolites at base

16

0

(m) Limestone, somewhat algal with sporadic crinoid stems [some encrusted by algae]; algae very abundant in a 14 in band at 2 ft 10 in from base, brachiopods and corals common just above this band; Dibunophyllum bourtonense φ, P. murchisoni, Davidsonina septosa, Monograptus sp. papilionaceus group, Bellerophon sp.

5

0

(l) Limestone, pale fine-grained slightly crinoidal; sporadic productoids and rare D. septosa

5

4

(k) Clay parting, on potholed surface

12 in to 0.5

(j) Limestone, pale fine-grained; scattered productoids and gastropods

4

0

(i) Lower D. septosa Band: limestone as above; rare P. murchisoni, common D. septosa

4

0

(h) Limestone, pale massive fine-grained; stylolite band 5 ft from top; 2-ft band at 7 ft from top with scattered productoids, D. septosa and a few large crinoid columnals

13

0

(g) Clay parting

0.5

(f) Limestone, pale fine-grained

5

0

(e) Limestone, pale fine-grained shelly; common productoids

3

0

(d) Clay parting, on potholed surface

0 in to 0.5

(c) Limestone, massive pale fine-grained, slightly crinoidal in upper part; sporadic productoids and rare D. septosa

7

3

(b) Not exposed about

1

0

(a) Limestones with potholed surface (in quarry floor)

The long section in Newlin Quarry starts in the lowest level of the quarry [SK 0917 7732] north of Peak Forest Station, and finishes mile to the north-west [SK 0888 7778]; the uppermost beds lie a little below the Upper D. septosa Band:

feet

inches

Limestone, pale fine-grained; a few crinoid stems in lowest 5 ft

18

0

Lower D. septosa Band: lithology as above; productoids, D. septosa, gastropods and crinoid debris

2

10

Limestone, pale fine-grained

4

9

Not exposed

12

0

Limestone, pale fine-grained; productoids and D. septosa in top 4 ft

7

0

Clay parting, on potholed surface with potholes up to 1.5 ft deep about

1

Limestone, pale massive fine-grained, with a 2.5-ft band with corals, D. septosa, productoids and gastropods 14 ft from top; stylolite band up to 9 in, 25 ft from top

37

0

Not exposed

4

0

Clay parting, on strongly potholed surface with dolomite crust

2 in to 9

Limestone, grey to dark grey variegated, fine-grained with irregular clay partings in places

1 ft to 3

0

Clay partingA thin section (E36118/P) shows a microcrystalline aggregate of pale brown clay mineral showing orientation along several directions, patchy weak anisotropism and abundant inclusions. The last-named comprise sub-microscopic dust, discrete heavy minerals (zircon, apatite, tourmaline) and an abundance of opaque sulphide needles, up to 80 microns long, generally tapering (up to 4 microns wide), geniculate, individual or stellate, and slightly curved in places. A polished thin section showed the needles to be anisotropic and they are identified as marcasite. They may have originated in microscopic tension cracks in the clay., on potholed surface (floor of top lift of quarry)

0 in to 6

Limestone, pale massive fine-grained; dark-mottled in top 2 ft; 1-ft algal band 15 ft above base

21

0

Clay parting, on potholed surface up

to 6

Limestone, pale grey-brown (slightly darker than overlying limestones)

3

6

Clay parting

0 in to 4

Limestone, off-white fine-grained; some darker mottling in top 2 ft; stylolite bands at top and base

5

3

Clay parting

0 in to 4

Limestone, off-white fine-grained, with scattered coarse crinoid debris; gastropods, corals and productoids in lowest 3 ft

7

6

Limestone, off-white fine-grained

2

0

Clay parting, grey-green where unweathered, on slightly potholed surface

2 in to 5

Limestone, pale grey-brown about

1

8

Clay parting, on potholed surface

1 in to 2

Limestone, off-white fine-grained; with thin clay wayboards at 4 ft 3 in and 6 ft 6 in from base; thin clay parting in places at base

16

6

Limestone, grey-brown massive fine-grained; rare P. murchisoni and productoids

15

6

Limestone, pale grey-brown massive fine-grained about

7

6

Smalldale, Peter Dale and Monk's Dale

Between Laughman Tor and Peter Dale an expanse of flat-lying or gently undulating Chee Tor Rock forms a broad outcrop. On the plateau surface exposures are numerous, but large sections are lacking. The tendency for fossils in the Chee Tor Rock to be restricted to more or less well-defined horizons enables small exposures of these in many cases to be correlated by calculating their position in relation to the top or base of the Chee Tor Rock.

At Laughman Tor the section (loc. 14) [SK 1015 7799] is as follows:

feet

(b) Limestone, pale grey well-bedded fine-grained; abundant corals; Dibunophyllum bourtonense cp, Lithostrotion aff. martini, L. pauciradiale, P. murchisoni, S. cf. geniculata, A. expansa, Gigantoproductus sp., Linoproductus sp., Monograptus sp. papilionaceus group, Pugilis?, smooth spiriferoids

10

(a) Limestone, grey-white massive fine-grained, part finely bioelastic and oolitic; top 20 ft sparsely fossiliferous; foraminifera, Dibunophyllum sp., Lithostrotion aff. martini, L. pauciradiale, Monograptus sp. papilionaceus group

30

The coral bed forms the craggy top of the tor. It lies about 140 ft below the top of the Chee Tor Rock (Figure 6).

To the south-east of Laughman Tor the Chee Tor Rock forms a gentle dip-slope, and at the Marvel Stones [SK 1045 7780] weathering of this has given rise to a limestone pavement, an infrequent feature in the area. A quarry [SK 1065 7810] in Smalidale Plantation shows a typical section: brown-white fine-grained limestone, rather crinoidal 10 ft, on pale grey or grey-white massive fine-grained limestone 13 ft.

Near Gorsey Nook a band bearing a diffuse brachiopod-coral fauna is exposed [SK 1042 7685] and has been traced laterally for a distance of about a quarter of a mile. The band lies about 100 ft below the top of the Chee Tor Rock at or near the horizon of the algal band near the base of the Duchy Quarry section. An outlier of the same bed is present at the western end of Middle Hill, an exposure (loc. 15) [SK 1079 7698] showing pale fine-grained limestone, sparsely fossiliferous near base 2 ft 2 in, on pale fine-grained limestone with Caninia sp. [?C. cf. densa Lewis of Hudson and Cotton 1945a, p. 306], Clisiophyllum sp. [juv Lithostrotion martini, Davidsonina septosa, Delepinea aff. comoides, Linoproductus aff. corrugates and Monograptus sp. papilionaceus group. On the east side of the hill lower beds are exposed, the section (loc. 16) [SK 1129 7706], with the uppermost beds [SK 1124 7696] lying about 10 ft below the band with D. septosa of the previous locality, being:

feet

(e) Limestone, off-white massive fine-grained in beds about 3-ft thick

36

(d) Limestone, grey-white fine-grained; coral band with Lithostrotion pauciradiale, L. sp. aranea group, Megachonetes sp.

3

(c) Limestone, off-white, rather well-bedded fine-grained; scattered brachiopods and corals

9.5

(b) Limestone, pale brown to off-white fine-grained; abundant corals in upper 3.25 ft and corals and brachiopods in lower 2 ft; fauna includes Caninia cf. densa [of Hudson and Cotton], Clisiophyllum keyserlingi, Dibunophyllum bourtonense φ, Koninckophyllum θ, L. junceum, L. martini, L. pauciradiale, L. cf. sociale, P. murchisoni, brachiopods including Gigantoproductus sp. maximus group

8

(a) Limestone, off-white, fine-grained

15

The thickness, rich coral fauna and estimated stratigraphical position of the lower band suggest equivalence to the coral band of Laughman Tor.

The upper coral band of the last section is more strongly developed (loc. 17) [SK 1059 7721] on the north-west side of Middle Hill where it is 6 ft thick and has yielded Lithostrotion cf. aranea, L. aff. maccoyanum, L. aff. martini and P. murchisoni.

Nearly 1.5 miles S.E. of the last locality two fossil-bands are present locally at closely similar horizons to those of Middle Hill. The upper band is the better developed and is exposed [SK 1231 7561] north-east of Hargate Hall in the following section (loc. 18):

feet

inches

(d) Limestone, near white very finely crystalline, with a little crinoid debris; a 9-in band at 2 ft from base with corals including L. martini, G. sp. edelburgensis group

about 5

0

(c) Clay, yellow on irregular potholed surface about

1

(b) Limestone, pale fine-grained, with irregular fracture, lower half fossiliferous; L. martini, A. expansa, G. sp. edelburgensis group, Linoproductus sp. hemisphaericus group

4

9

(a) Limestone, pale massive fine-grained; rare corals including Lithostrotion martini 3.5 ft 6 below top

6

A band some 40 ft lower in the succession and 4.75 ft thick is exposed nearby [SK 1241 7553] and yields brachiopods and corals; this appears to be about 150 ft below the top of the Chee Tor Rock. The two bands crop out on the south-western limb of a small sharp anticline traceable for a distance of half a mile and trending N.W.–S.E. The Monk's Dale Vent, first noted by Arnold-Bemrose (1907, p. 251), more fully described on p. 300, lies at the south-eastern end of the anticline near the axis and a further vent has been found mile to the north-west and lying close to the anticline. The association of these two vents with a sharp anticline, foreign to the tectonic pattern of the limestone massif, suggests strongly that the structure was of penecontemporaneous origin.

The relationship of the vents to the anticline is illustrated in (Figure 14).

In Peter Dale the lower part of the Chee Tor Rock is exposed nearly continuously. Beds low in the subdivision stand out as a marked cliff of massive limestones showing the characteristic vertical jointing at Dale Head. The massive beds forming the cliff are underlain by some 40 ft of thinner-bedded limestones. A coral band up to 4 ft thick is present at the base of the Chee Tor Rock in the eastern tributary dale at Dale Head above the section (loc. 2) [SK 1248 7653] of Woo Dale Beds described on pp. 39–40:

feet

(g) Limestone, medium to pale grey-brown massive fine-grained; Koninckophyllum sp. [compound] 4 ft below top; L. martini and Monograptus sp. papilionaceus group 10 ft below top

25

(f) Coral band, lithology as above except for 4-in darker limestone at base; D. bourtonense φ. Koninckophyllum θ, L. junceum?, L. martini, L. pauciradiale, P. murchisoni, Antiquatonia aff. insculpta, Athyris expansa, Dielasma hastatum, Gigantoproductus? sp. nov. [wrinkled concentric ornament], Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group

3.5

Woo Dale Beds

At Dale Head the coral band (f) disappears laterally but it reappears farther north in the long section at the junction of Hay Dale and Dam Dale (p. 50). The section (loc. 1) in the main dale at Dale Head [top of section: [SK 1232 7630] shows higher beds in the Chee Tor Rock:

feet

(i) Limestone, pale fine-grained massive (forming crags); band 5 ft from base with Carcinophyllum vaughani, Lithostrotion martini, A. expansa, Monograptus sp. papilionaceus group

24

(h) Beds poorly exposed. Some small exposures of grey limestone; one at 15 ft from top with Dibunophyllum bourtonense φ, Dielasma hastatum, G. sp. maximus group, G.? sp. nov. [wrinkled concentric ornament], Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group

26

(g) Limestone, pale massive (forming crags); 6-ft coral band 15 ft from base (fauna see loc. 19 below); at 8 ft from base, Lithostrotion martini

26

(f) Limestone, pale rather thin-bedded fine-grained; at 20 ft above base, Monograptus sp. papilionaceus group

40

Woo Dale Beds (see p. 39)

Some 55 ft above the base of the Chee Tor Rock is a well-developed coral band, bed (g) of the preceding section. This is best seen (loc. 19) in a small cliff on the west side of Peter Dale [SK 1222 7626], where it is 6 ft thick and yielded C. vaughani, D. bourtonense φ, Lithostrotion martini, L. pauciradiale, L. cf. sociale, P. murchisoni, A. expansa, Gigantoproductus? sp. nov. [wrinkled concentric ornament], Linoproductus sp. hemisphaericus group and Monograptus sp. papilionaceus group. The overlying limestones, exposed in Peter Dale between the coral band and the vents previously noted, show their usual lithological characters but no fossil bands were found. Near the Monk's Dale vents, however, a 2-ft band overlying 80 ft of unfossiliferous beds on the eastern side of the dale (loc. 20) [SK 1304 7539] yielded Lithostrotion martini, Linoproductus sp. hemisphaericus group and Monograptus sp. papilionaceus group. The band appears to lie about 140 ft below the top of the Chee Tor Rock and to be the equivalent of the lower of the two fossil bands exposed north-east of Hargate Hall. The higher horizon is probably present in an exposure (loc. 21) [SK 1347 7521] near Monks-dale House as 3 ft of grey limestone with Caninia benburbensis and D. bourtonense φ.

Between Monk's Dale and Tideswell Dale the Chee Tor Rock crops out over a broad plateau which, however, shows only minor exposures.

To the east of the outcrop the only information regarding the underground extension of the Chee Tor Rock, is provided by the Derwent Valley Water Board's trial borehole at Litton Dale [SK 1599 7498]. The borehole was not cored and the record is from the borers, supplemented by examination of cutting-samples by Professor F. W. Shotton. The base of the Lower Lava was found at 243 ft and from thence to 340 ft the hole passed through pale fine-grained limestones with some pyrite in the uppermost 5 ft. These beds represent the topmost part of the Chee Tor Rock. Below 340 ft the succession is abnormal, the beds to the bottom of the borehole at 385 ft being either lava with calcitization in places or interbedded lava and tuff. Extrusive igneous rock at this horizon is unknown elsewhere in the district, though this is not the earliest evidence of vulcanicity in the area.

Wheston to Ox Low

Between Wheston and Dale Head faulting brings up beds low in the Chee Tor Rock to crop out on the plateau surface. An exposure (loc. 22) [SK 1270 7637] west of Wheston Hall (see (Figure 6)) showed a coral band 2 ft thick and about 100 ft above the base with Lithostrotion portlocki, Syringopora cf. distans, Gigantoproductus dentifer, Linoproductus sp. hemisphaericus group and Monograptus sp. papilionaceus group. A nearby exposure (loc. 23) [SK 1273 7630] yielded Lithostrotion martini and P. murchisoni from the same band.

Higher up the slope, towards Wheston, an exposure (loc. 24) [SK 1286 7623] shows a 21-in band with Lithostrotion martini, L. pauciradiale, P. murchisoni?, Davidsonina septosa and Linoproductus sp. hemisphaericus group. This exposure lies some 150 ft below the top of the Chee Tor Rock and is at or near the horizon of the coral band of Loughman Tor (see p. 47).

A higher coral band is present over a distance of 300 yd farther up the slope and lies some 100 ft below the top of the Chee Tor Rock. An exposure (loc. 25) [SK 1295 7618] shows the band some 8 ft thick with Dibunophyllum sp., Lithostrotion decipiens?, L. martini, P. murchisoni and Linoproductus sp. hemisphaericus group. These beds rest on a potholed surface with yellow clay which, if equivalent to that developed north-east of Hargate Hall, suggests that the lower part of the band has failed.

At the junction of Hay Dale and Dam Dale the following section (loc. 3) in the lowest part of the Chee Tor Rock, continues that of the Woo Dale Beds given on p. 40 [top of section 1190 7727]:

feet

Limestone, grey-white to brown-white massive fine-grained; 44 ft from base (s) Lithostrotion junceum; 34 ft from base (r) Dibunophyllum hourtonense, Lithostrotion martini, L. portlocki, P. murchisoni, bryozoa, A. cf. expansa, G. dentifer, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group, gastropods; 2 ft from base a 1-ft band (q) yields Caninia cf. densa [of Hudson and Cotton], D. bourtonense φ, Koninckophyllum θ, Lithostrotion junceum, L. martini, L. pauciradiale, L. cf. sociale, P. murchisoni, bryozoa, Dielasma hastatum, Gigantoproductus spp., including G. ? sp. nov. [wrinkled concentric ornament], Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group, gastropods

45

Woo Dale Beds

The coral band at the base is the same as that developed in this position at Dale Head (loc. 2, p. 49). Higher beds in the Chee Tor Rock, uniformly pale, massive and fine-grained, are exposed on the east side of Hay Dale for a distance of a quarter of a mile above this section; beyond here, however, they are faulted off.

About 100 ft from the base of the Chee Tor Rock, on the slopes east of Hay Dale (loc. 26) [SK 1225 7721] a band (traceable for some quarter of a mile) 5 ft thick yields Lithostrotion martini, P. murchisoni, bryozoa, Delepinea aff. comoides and Linoproductus sp. hemisphaericus group. The band appears to be that developed as a coral band west of Wheston (loc. 22, see above).

Between Hay Dale and Hemstone Lane Head the coral band at the base of the Chee Tor Rock is developed in places. At Hem-stone Lane Head the section (loc. 4) of the lowest part of the subdivision is continuous with that of the Woo Dale Beds given on p. 41 [top of section 1226 7876]:

feet

(i) Limestone, pale grey-brown massive fine-grained in beds up to 3.5 ft

10

(h) Not exposed

about 14

(g) Limestone, pale brown finely granular; top 1 ft with Lithostrotion aff. martini, Monograptus sp. papilionaceus group

6

(f) Limestone, pale grey-brown very fine-grained, white-weathering

3 in to 0.5

(e) Limestone, pale grey finely crinoidal, corals and brachiopods in pockets near base; Dibunophyllum sp., L. junceum, L. martini, P. murchisoni, bryozoa, G. sp. maximus group

19

Woo Dale Beds

Farther east the Chee Tor Rock forms a broad outcrop with sporadic exposures only. The Lower D. septosa Band, some 60 ft below the top, is exposed in a small limestone scar and can be traced for some hundreds of yards at the crest of a small hill west of Potluck House. An exposure (loc. 27) [SK 1294 7805] shows the band, 2 ft thick, with corals including Caninia sp. subibicina group, P. murchisoni, Davidsonina septosa, Delepinea aff. comoides, Linoproductus sp. hemisphaericus group.

At Wall Cliff the uppermost beds of the Chee Tor Rock are exposed in the following section (loc. 28) [SK 1424 7738]:

feet

inches

(j) Lower Lava (see p. 53)

(i) Limestone, pale to medium grey well-bedded fine-grained; Dibunophyllum bourtonense φ

6

0

(h) Calcilutite, pale to medium grey finely banded

6

(g) Limestone, pale and dark grey variegated, slightly tuffaceous

3

3

(f) Cakilutite, grey-white, part finely banded

2

1

(e) Limestone, grey-white

1

4

(d) Limestone, pale fine-grained with 'hackly' weathering in beds up to 1 ft; Lithostrotion junceum at 1 ft 4 in from base

4

6

(c) Calcilutite, white weathering, ?algal

0 in to 6

(b) Limestone, pale fine-grained; Lithostrotion martini, Linoproductus sp. hemisphaericus group

1

3

(a) Limestone, massive pale fine-grained; liackly' weathering, with a little darker variegation in lowest 13 ft

33

0

The presence of calcilutite bands high in the Chee Tor Rock is a striking feature of the section and recalls that at Bold Venture Quarry (see p. 46).

At the northern end of the outcrop the Chee Tor Rock is well seen on Ox Low. A shell band is present locally on the southwest side of the hill and is seen on the north side of old open workings on Oxlow Rake (loc. 29) [SK 1260 8002] in the top 6 ft of a 40-ft section. This bed yielded P. murchisoni, Gigantoproductus sp. and Linoproductus sp. Some 90 ft higher in the succession, the Upper D. septosa Band is exposed [SK 1265 8014] as a 2-ft band with brachiopods (including D. septosa) and gastropods. This band lies about 30 ft below the base of the Lower Lava and the total thickness of the Chee Tor Rock hereabouts is about 300 ft.

To the north of Ox Low, with the disappearance of the Lower Lava the Chee Tor Rock and Miller's Dale Beds are considered together as the Bee Low Limestones.

Lower Miller's Dale Lava
Water Swallows, Great Rocks Dale and Dove Holes

The outcrop of the Lower Lava enters the district half a mile south of Water-swallows but is almost immediately cut out by the transgressive Waterswallows Sill. The latter has, however, been cut through in Waterswallows Quarry [SK 0860 7504] to show up to 6 ft of pale calcitized amygdaloidal lava resting on limestone and with an irregular junction with the overlying dolerite. Near this junction the lava usually contains pyrite veins and pyrite amygdales. The altered lava has been recently compared by Dr. F. Moseley (in discussion Dunham and Kaye 1965, p. 275) to the White Whin of the Durham area.

To the east of Water Swallows, faulted outliers of the lava are present north of Tunstead Quarry though they are much obscured by tipping. A section [SK 0979 7538] near the railway shows 13 ft of amygdaloidal lava in a down-faulted wedge.

On the eastern side of Great Rocks Dale the Lower Lava has been passed through in a number of boreholesPublished by permission of Imperial Chemical Industries Limited.. The greatest thickness was proved in the southernmost hole T/13/21 [SK 1034 7547], which gave the following abridged succession:

Thickness

Depth

feet

inches

feet

inches

Limestone (Miller's Dale Beds)

60

3

60

3

Clay, yellow-brown soft ('toadstone clay')

5

10

66

1

Lava, soft and with pyrite to 67 ft 9 in; hard and amygdaloidal below

6

11

73

0

Clay

2

2

75

2

Lava, dark, some amygdales, to 78 ft 6 in, mainly non-vesicular to 97 ft 7 in; amygdaloidal to 104 ft 2 in; non-vesicular, with hematite specks to 107 ft

31

10

107

0

Clay, reddish brown

2

107

2

Lava, grey-green with hematitic joints to 110 ft 6 in; part vesicular to 129 ft 3 in; dark and non-vesicular to base

37

6

144

8

Tuff, pale grey-green pyritous with chlorite specks

13

9

158

5

Limestone

27

7

186

0

The lava shows a clear division into three flows separated by the clay partings at 75 ft 2 in and 107 ft 2 in. A similar but thinner section was proved farther north in borehole T/B/23A [SK 0985 7614] which started just below the top of the lava and showed 74 ft 8 in of it.

To the west and south-west of Upper End the Lower Lava forms a broad outcrop over the crest of a shallow anticline; in places it is capped by small outliers of Miller's Dale Beds. In this area the outcrop bears frequent swallow-holes, many of which provide sections of the lava. For example, north-east of Water Swallows [SK 0836 7557] where 14 ft of amygdaloidal lava are exposed. Near Batham Gate the lava is 50 to 60 ft in thickness. An exposure [SK 0840 7644], again in a sink-hole, shows 12 ft of amygdaloidal lava. The most northerly exposure on this outcrop of lava in a more or less unaltered state is [SK 0801 7753] 0.5 mile S.E. of Dove Holes station. Between Dove Holes and Lodes Marsh the lava thins steadily, the outcrop showing as a depression with bright yellow clay visible in places. The lava finally disappears [SK 0865 7836] at Lodes Marsh.

Wormhill Moor, Tunstead and Hargatewall

To the east of Great Rocks Dale the Lower Lava crops out around the high ground forming Wormhill Moor. Near Rock Houses the thickness of the lava is about 75 ft but it thins northwards to 30 ft at the northern end of the outcrop near Smalldale. Sections are infrequent though the lowest beds, reddish weathering and amygdaloidal, are well seen close above the abandoned Great Rocks Quarries [SK 0956 7633].

Around the hamlet of Tunstead and at Hargatewall the Lower Lava reaches its maximum thickness of about 100 ft. It is well exposed, for instance, in the sides of the lane [SK 1106 7471] 350 yd S. of Tunstead. Locally, hard dark compact non-amygdaloidal basalt of rather coarse grain is present in small masses within the Lower Lava, as at [SK 1132 7467] south-east of Tunstead and is considered to be the middle part of a flow.

Tideswell Dale to Bradwell Moor

The outcrop of the Lower Lava enters the district at Tideswell Dale but is here complicated by the presence of the Tideswell Dale Sill at the base. On the east side of the dale [SK 154 744] features suggest the splitting of the Lower

Lava with the development of a thin limestone parting, too small to be shown on the one-inch map. The most northerly outcrops in Tideswell Dale are faulted and may not represent the whole of the Lower Lava; the sequence is best illustrated by the Litton Dale Borehole [SK 1599 7498] (see also p. 55). This is as follows:

Thickness

Depth

feet

feet

Base of Miller's Dale Beds

152.5

Tuff

2.5

155

Lava

64

219

Limestone, light grey and dark grey; silicified near base

12

231

Lava

12

243

Chee Tor Rock (see n_ 501

From Tideswell Dale the outcrop of the Lower Lava is faulted westwards to Heathydale Ward. Around Wheston the thickness of the lava is about 90 ft, but to the north it thins, only some 40 ft being present around Potluck. Near here an exposure 11303 77121 shows non-vesicular lava 6 ft on amygdaloidal lava 7 ft.

At Wall Cliff the section (loc. 28, see also p. 51) shows the Lower Lava [SK 1433 7731] to be 35 ft thick. It is poorly exposed but where seen shows its normal amygdaloidal character. Farther north, at the intersection of the outcrop with White Rake, strike-faulting brings the Upper Lava and the Lower Lava into juxtaposition. An exposure of the latter, deeply weathered, is visible to a depth of 7 ft in an openwork on the vein [SK 1452 7815].

The most northerly exposures worthy of note are at The Cop; these show amygdaloidal lava [SK 1287 7968] and, 60 yd farther north, non-vesicular lava. The total thickness here is some 30 ft. To the north of The Cop the Lower Lava thins rapidly and disappears [SK 1355 8108] near Hazard Mine.

The isolated occurrences of Lower Lava at Cave Dale and of tuff at a comparable horizon at Pin Dale are, for geographical reasons, best considered with the Bee Low Limestones.

Miller's Dale Beds
Water Swallows and Dove Holes

On the southern margin of the district the Miller's Dale Beds form a broad outcrop west of Water Swallows. A section in an old quarry [SK 0707 7457] on Fairfield Common, shows 18 ft of pale massive limestone, Shelly in the lowest 1 ft and with sporadic productoids and corals in a 3.5-ft band at 5.5 ft from the base. To the east of the main outcrop, faulted outliers of Miller's Dale Beds overlie the Lower Lava in places on a shallow ridge between Hardy-barn and Batham Gate. Between Batham Gate and Dove Holes the Dove Holes Tuff is present within the lower half of the subdivision.

Between Batham Gate and Bibbington the Miller's Dale Beds have been proved in a number of boreholes for quarry development. Borehole No. 11 of this series [SK 0749 7674] proved the full thickness of the Miller's Dale Beds':

Thickness

Depth

feet

feet

Base of Monsal Dale Beds

140

Limestone, grey and light grey, thick-bedded; sporadic large productoids

88

228

Dove Holes Tuff: grey pyritous clay with limestone lapilli at base

5

233

Limestone, as above but nearly porcellanous in places

49

282

Lower Lava

The outcrop of the Dove Holes Tuff is traceable for a stretch of 300 yd to the east of Peak House. To the south of a line between Peak House and the site of borehole No. 11 this tuff cannot be located at outcrop and it has also been proved absent by several bore-holes. No. 13 Borehole [SK 0780 7628] near Field Farm, however, showed 7 ft 6 in of 'greenish ash with pyritesInformation from examination of cores by Professor F. W. Cope. with base at 89 ft on 11 ft of 'blue limestone' overlying the Lower Lava. This is the only record of a tuff at this horizon in the area.

The upper part of the Miller's Dale Beds is well exposed in Victory Quarry (loc. 30) [SK 0774 7693] 0.25 mile N.W. of Peak House, the lowest beds lying within a foot or two of the Dove Holes Tuff:

feet

inches

Monsal Dale Beds (see pp. 63, 65)

(j) Limestone, pale fine-grained; 3-in band with productoids 8 ft from base

22

0

(i) Limestone, pale fine-grained; Lithostrotion junceum, L. martini, P. murchisoni, Linoproductus sp. hemisphaericus group about

1

4

(h) Limestone, pale massive fine-grained, with scattered crinoid debris

18

0

(g) Limestone, pale very fine-grained

4

0

(f) Clay parting, on potholed surface, both dying out laterally up to

1

(e) Limestone, pale massive, with a little fine erinoid debris; shelly in top 2 ft

7

0

(d) Shale, on irregular surface of limestone about

2

(c) Limestone, pale fine-grained; gastropods in top 2 ft and productoid fragments 3 ft from top

11

0

(b) Limestone, grey-brown finely crinoidal

4

0

(a) Limestone, pale brown very fine-grained

16

0

A section complementary to the above is that in Dove Holes Dale Quarry (loc. 31) [SK 0782 7748]. This shows the Dove Holes Tuff and some of the underlying beds:

feet

inches

Limestone, pale grey well-bedded finely crinoidal

7

0

(e) Limestone, pale grey banded fine-grained, finely crinoidal and slightly oolitic; productoids including L. sp. hemisphaericus group

11

(d) Limestone, pale grey massive fine-grained

5

4

(c) Dove Holes Tuff: much grassed over, grey clay with rounded limestone lapilli visible at 2.5 ft up, yellow clay at base on strongly potholed surface

5

0

(b) Limestone, grey-brown massive fine-grained

8

0

(a) Limestone, pale massive fine-grained, fossiliferous in top 8 ft; Dibunophyllum bourtonense φ, Lithostrotion cf. martini, P. murchisoni, Davidsonina septosa and Linoproductus sp. hemisphaericus group

24

0

The Dove Holes Tuff was originally described by Arnold-Bemrose (1907, p. 253) from a quarry near the Bull Ring, but this is now covered by tip. Farther east it is well seen in the section in Holderness Quarry (loc. 32) (Plate 3B) [SK 0842 7817];

feet

(e) Limestone, medium grey-brown well-bedded fine-grained, with sporadic shells; G. edelburgensis

13

(d) Dove Holes Tuff: grey clay with limestone lapilli up to 0.5 in, thinning to 3.5 ft at south end of section; surface with potholes up to 15 in deep at base

6

(c) Limestone, very fine-grained massive off-white; corals throughout include Dibunophyllum bourtonense φ, Lithostrotion cf. martini; brachiopods in upper part include Davidsonina septosa and Linoproductus sp. hemisphaericus group

40

(b) Not exposed (position of quarry floor) about

2

(a) Limestone, near-white, massive fine-grained; top 1.5 ft with productoids and a few corals

13.5

The lowest beds of this section lie within a foot or two of the top of the Lower Lava.

The uppermost part of the Miller's Dale Beds is visible in the section (loc. 33, bed a) [SK 0799 7828] near the Bull Ring where 9.5 ft of pale grey fine-grained thick-bedded limestone with Gigantoproductus crassiventer and other brachiopods are overlain by Monsal Dale Beds (see p. 65). To the north of Near Ridge-close the Miller's Dale Beds and Chee Tor Rock are grouped together as the Bee Low Limestones.

Wormhill Moor and Hargatewall

To the south of Hargatewall the Miller's Dale Beds form a broad outcrop, approximating to a dip-slope. The best section [SK 1207 7482] near Hargate Hall, shows 11 ft of off-white fine-grained and finely crinoidal limestone with gastropods near the top. Another section [SK 1267 7475] near Wormhill Hall shows 5 ft of pale crinoidal and slightly oolitic limestone with shell debris.

To the north-west of Hargatewall a tongue-like area of Miller's Dale Beds is present beneath and around the outlier of Wormhill Moor. On the south-east side of this area the subdivision is thinly developed, only some 75 ft being present, while at the northern end, near Smalldale, the thickness is about 100 ft. The lowest beds, a few feet above the Lower Lava, are exposed in a roadside quarry north-west of Hargatewall (loc. 34) [SK 1120 7598]: 12 ft of off-white massive fine-grained limestone, slightly crinoidal with, in the top 6 ft, a fauna including Caninia benburbensis, Lithostrotion martini, P. murchisoni, Linoproductus sp., Monograptus sp. papilionaceus group and gastropods. On the western side of Wormhill Moor the Miller's Dale Beds are little seen, except for poor exposures of the lowest beds. At the northern end of the outcrop, however, near Smalidale, they are both well exposed and very fossiliferous. A section in a small quarry (loc. 35) [SK 0977 7700] is as follows:

feet

inches

(d) Limestone, white massive fine-grained with columnar jointing, scattered fossils throughout but more fossiliferous in top 4 ft; Caninia cf. densa [of Hudson and Cotton], Lithostrotion portlocki, A. cf. expansa, Davidsonina septosa, D. septosa towards transversa, Delepinea aff. comoides, Linoproductus sp. hemisphaericus group

23

0

(c) Limestone, white massive fine-grained; Dibunophyllum bourtonense, Lithostrotion martini, L. pauciradiale, P. murchisoni, Linoproductus sp. hemisphaericus group

11

2

(b) Limestone, very pale grey; D. bourtonense φ, Lithostrotion martini, L. pauciradiale, P. murchisoni about

1

10

(a) Limestone, soft tuffaceous

0 in to 4

Clay, yellow; top of Lower Lava

Tideswell to Old Moor

To the south of Tideswell the Miller's Dale Beds form a broad spread between Heathydale Ward and Tideswell Dale. They are well exposed in the latter south of its junction with Litton Dale. The Litton Dale Borehole [SK 1599 7498] (see also pp. 50–53) proved the Miller's Dale Beds as pale limestones between the base of the Station Quarry Beds at 55 ft and the top of the Lower Lava at 152 ft 6 in.

To the west of Tideswell, exposures of pale massive fine-grained limestone of the Miller's Dale Beds are fairly frequent. An exposure (loc. 36) [SK 1402 7574] near Crossgate, starting some 30 ft above the Lower Lava, showed 18 ft of pale massive fine-grained limestone with Saccamminopsis? 3 ft from the top.

Between Wheston and Wall Cliff, the Miller's Dale Beds form a broad outcrop showing small exposures only of uniformly pale massive fine-grained limestone. These beds give rise to a marked feature at Wall Cliff where the section (loc. 28) (overlying the Lower Lava at about 1440 7726) continues that given on pp. 51–53:

feet

Tuff (horizon of Upper Lava)

(p) Not exposed about

5

(o) Limestone, massive, fine-grained with a little irregular silicification; L. martini, L. pauciradiale, G. sp. maximus group

12

(n) Not exposed

6

(m) Limestone, buff massive; Aulina furcata, L. junceum, L. pauciradiale, Dielasma hastatum, Pugnax pugnus

8

(l) Not exposed

10

(k) Limestone, grey-white massive fine-grained; coral band 2.75 to 4.33 ft thick at 4 ft above base and corals at 11 ft 6 in above base; A. furcata, L. cf. maccoyanum, L. martini, L. pauciradiale, G. sp. maximus group

22

(j) Lower Lava

The total thickness, 63 ft, of the Miller's Dale Beds is the minimum found in the area. The coral band at the base of the section is correlated with the Lithostrotion aff.maccoyanum band found above the Lower Lava at Castleton (Shirley and Horsfield 1940, p. 276) and in the Wye valley (Cope 1933, p. 132).

Between Wall Cliff and White Rake the Miller's Dale Beds are cut out by a strike-fault. They are, however, present between White Rake and The Cop, though displaced somewhat by Shuttle Rake and Moss Rake. A section [SK 1380 7875] near the base of the subdivision on Tideswell Moor shows 9 ft of pale fine-grained limestone.

To the north of Batham Gate the lowest part of the Miller's Dale Beds shows its typically fossiliferous character. A section [SK 1351 7939], over 0.25 mile W.N.W. of The Holmes, shows 2 ft of near-white fine-grained limestone with corals, Davidsonina septosa and productoids. Farther to the north-west, "at Cop Round" Shirley and Horsfield (1940, p. 276) record a coral band with Lithostrotion cf. arachnoideum and L. aff. maccoyanum about 20 ft above the base of the Miller's Dale Beds. The feature of Cop Round [SK 1302 8002] is formed by the lowest part of the Monsal Dale Beds and it would appear that Shirley and Horsfield were' referring to a locality a little west of this. The thickness of the Miller's Dale Beds hereabouts is about 80 ft.

To the north and north-west of Old Moor the Miller's Dale Beds are not separately recognized.

Bee Low Group (D1): Northern area

Bee Low Limestones
Bee Low and Gantries Hill

The Bee Low Limestones are well displayed on Bee Low and, three-quarters of a mile to the east, on Lower Bee Low. To the east again of Lower Bee Low, the lowest beds are ill exposed. On Lower Bee Low a section [SK 1019 7920], starting about 200 ft above the base of the subdivision, showed 83 ft of pale massive fine-grained limestone. Farther west and probably slightly higher in the succession the following section (loc. 37) [SK 0970 7909] is exposed:

feet

(e) Limestone, massive pale fine-grained, with scattered corals; Dibunophyllum ? and L. martini

14

(d) Coral band with L. cf. martini and L. pauciradiale

2

(c) Limestone, as above; at 25 ft above base, Dibunophyllum bourtonense φ, L. arachnoideum, L. junceum, L. martini, Palaeosmilia murchisoni, Monograptus sp. papilionaceus group

29

(b) Coral band, with D. bourtonense φ, Lithostrotion junceum, L. martini, L. pauciradiale, L. cf. sociale, P. murchisoni, Athyris expansa, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group

3

(a) Limestone, as above; at 4 ft from top, Lithostrotion martini, L. pauciradiale, G. dentifer, Monograptus sp. papilionaceus group; at 13 ft from top D. bourtonense φ, L. pauciradiale, Gigantoproductus ? sp. nov. [wrinkled concentric ornament], Linoproductus sp. hemisphaericus group; at base, Lithostrotion cf. martini

25

The lower of the two coral bands in this section is thus about 260 ft above the base of the Bee Low Limestones and the band is correlated with at least the lower part of the coral-bearing beds of Laughman Tor (see p. 47).

Separated from the above section by a fault and perhaps 50 ft higher stratigraphically, is a band [SK 0938 7903], 1 ft 3 in thick, with Davidsonina septosa and productoids. This band appears to be in that part of the succession where the Upper and Lower D. septosa bands occur, though it cannot be precisely correlated owing to faulting. The same band has also been located at the eastern end of the Bee Low Quarry section though again in the fault-zone. The section in the quarry (loc. 38) [SK 0922 7915] is as follows:

feet

(l) Limestone, pale massive; white and very fine-grained in top 4 ft with rare gastropods and corals

12

(k) Clay parting, on potholed surface up to

1.5

(j) Limestone, pale massive about

65

(i) Limestone, medium grey (conspicuous in face)

3.5

(h) Limestone, pale massive; clay parting locally up to 1 ft thick at 6 ft above base

15

(g) Clay parting, on potholed surface

(f) Limestone; P. murchisoni

4.5

(e) Limestone, rather crinoidal, with scattered coarser columnals ; some large D. septosa and productoids ductoids

8

(d) Limestone, pale fine-grained, with scattered fine crinoid debris

8

(c) Limestone, fine-grained bioelastic, oolitic in places; occasional large crinoid stems and small algal colonies; P. murchisoni

12

(b) Limestone, pale fine-grained, with coarse crinoid debris in top 6 ft

45

(a) Limestone, pale fine-grained (not all accessible); at about 50 ft above base, L. martini and P. murchisoni

120

The field evidence suggests that the uppermost beds lie some 80 ft below the base of D2. The medium grey limestone (i) is considered to lie at the horizon of the Lower Lava. The underlying occurrence of D. septosa would then be at the horizon of the Upper D. septosa Band.

To the south-east of Bee Low, an exposure [SK 0953 7868] near Lodesbarn shows fine-grained finely crinoidal and slightly oolitic limestone 2.25 ft on brown calcilutite 3.25 ft. The stratigraphical position of this exposure is difficult to estimate though it must be near the middle of the Bee Low Limestones. A similar calcilutite band has already been noted (see p. 46) near the top of the Chee Tor Rock at Upper End.

Exposures on both sides of the main road between Sparrow Pit and Peak Forest provide a good cross-section of the Bee Low Limestones. The lowest beds, perhaps 370 ft thick, are well exposed south-east of Harratt Grange and show in general a lithology typical of this part of the D1 succession, though the lowest beds are somewhat oolitic e.g. [SK 1026 7966]. Higher beds are exposed in Haddocklow Plantation, the section [SK 0984 8024] being:

feet

Limestone, pale massive slightly crinoidal

16.5

Coral band, with P. murchisoni (horizon of Upper D. septosa Band)

2.5

Limestone, as above

6

Not exposed

about 22

Limestone, pale massive fine-grained, with scattered productoids, D. septosa and corals (horizon of Lower D. septosa Band)

10.5

The upper band yielded D. septosa in the south-eastern corner of Haddocklow Plantation [SK 0992 8001]. The correlation of the two bands is on the basis of their position within the Di sequence.

Some 250 ft of limestones, intermittently exposed, overlie the Upper D. septosa Band. These contain, in Gautries Plantation [SK 0937 8058], a 16-in crinoidal band with sporadic D. septosa. This is tentatively correlated with the higher of the two D. septosa bands on Eldon Hill (see below).

The lowest part of the Bee Low Limestones is well exposed in Perry Dale where some 300 ft of these beds are present between the base of the subdivision and the point where lateral passage into apron-reef takes place. The lowest beds are finely crinoidal, though less so than the underlying Peak Forest Limestones. Within 200 yd of the reef margin the Bee Low Limestones develop thick lenses of shelly, poorly bedded limestone of reef type; such beds are referred to the transitional back-reef facies (see (Plate 11)) and an exposure of these is seen (loc. 39) [SK 1005 8087] on Gautries Hill:

feet

(c) Limestone, pale fine-grained; L. martini, orthocone nautiloid fragments and Bollandoceras sp. nov.

9

(b) Shell band; L. martini, Antiquatonia cf. insculpta, Dielasma hastatum, Linoproductus sp. ?hemisphaericus group, Monograptus sp. papilionaceus group, Productus productus

2.5

(a) Limestone, pale fine-grained

9

Both in their geographical relation to the reef-belt and their well-bedded character, the limestones of this exposure should clearly be referred to the shelf succession. However, the rich brachiopod fauna and particularly the presence of a goniatite shows faunal affinities with the reef-belt.

On the south side of the summit of Gautries Hill the inward dips towards the shelf area, frequent at the margin of the reef-belt, are present. Such dips are, however, not developed in Perry Dale.

Eldon Hill to Windy Knoll

On Eldon Hill much of the Bee Low Limestones is present. The lower beds, 280 ft thick, were proved in the water borehole at Eldon Hill Quarry [SK 1128 8156] as pale fine-grained limestones. Higher beds are exposed in the quarry (loc. 40) [SK 1128 8134]:

feet

(f) Limestone, pale massive well-bedded

40

(e) Limestone, medium to rather dark grey about

5

(d) Clay parting

(c) Limestone, pale massive well-bedded; 1 ft Shelly band 9 ft from top; scattered brachiopods and gastropods in lowest 20 ft

60

(b) D. septosa band; Dibunophyllum bourtonense, Lithostrotion martini, L. portlocki, Antiquatonia cf. insculpta, Athyris expansa, Davidsonina septosa, gastropods, nautiloid, trilobite, ostracods

12

(a) Limestone, pale grey; scattered fossils including L. martini; a pocket of very fossiliferous grey-brown limestone at about 50 ft above base in the northeastern corner of the quarry [SK 1135 8148], with L. junceum, L. martini, Antiquatonia cf. insculpta, Athyris expansa, Dielasma hastatum, Gigantoproductus edelburgensis, G. sp. cf. moderatus, Overtonia fimbriata, gastropods and bivalves

110

The D. septosa band of this section lies some 300 ft above the base of D1. The fossiliferous lenses are indicative of the nearness of the reef-belt.

Some 150 ft above the D. septosa band of the quarry, another band is present on the eastern side of Eldon Hill. This is well seen in an old quarry [SK 1218 8102]:

feet

Limestone, pale well-bedded fine-grained

4.25

Minor erosion surface

Limestone, as above; with 1-ft band with Davidsonina septosa and corals at top

6

Over much of Eldon Hill, however, the higher band is ill defined. It was considered by Shirley and Horsfield (1940, p. 275) to be at or about the horizon of the Upper D. septosa Band of the Miller's Dale succession. The band or its horizon cannot, owing to probable displacement by Watt's Grove Vein, be traced into the proved succession at Ox Low, but the general geometry of the outcrop suggests rather that the D. septosa band of the quarry is the Upper D. septosa Band of the standard succession, and that the higher band, on Eldon Hill, represents the Lithostrotion aff. maccoyanum horizon.

On the south-west side of Eldon Hill the following section (loc. 41) [SK 1124 8077] shows beds at and below the Upper D. septosa horizon:

feet

inches

(j) Limestone, medium to dark grey; slightly oolitic in top 5.5 ft, very fine-grained below (horizon of Upper D. septosa Band); Lithostrotion martini, L. pauciradiale, P. murchisoni, A. expansa, Monograptus sp. papilionaceus group

6

6

(i) Not exposed about

27

0

(h) Limestone, pale algal; Linoproductus sp. hemisphaericus group

1

6

(g) Limestone, pale finely bioclastic

2

0

(f) Limestone, pale algal; L. martini

1

7

(e) Limestone, pale very fine-grained

1

0

(d) Limestone, pale algal, rare crinoid debris; A. expansa, Monograptus sp. papilionaceus group

8

(c) Limestone, pale fine-grained, with some crinoid debris

2

9

(b) Limestone, pale crinoidal; L. martini

2

2

(a) Limestone, pale fine-grained

1

9

The concentration of algae below the Upper D. septosa Band recalls the same association as that in other localities, for example Upperend Quarry (see p. 46).

Beds above and including the Upper D. septosa Band are exposed on the flank of a hill east of Snels Low [SK 1157 8164]:

Limestone, pale fine-grained [SK 1168 8171]

10

Not exposed

6

Limestone, pale oolitic, with some fine bioclastic material and a little fine crinoid and shell debris; D. septosa and some corals

9.5

Beds poorly exposed; loose blocks indicate coral band, up to about 3-ft thick, 4 ft from top

26

Limestone, pale fine-grained

2

Not exposed

24

Limestone, pale fossiliferous, somewhat oolitic in top 1 ft; scattered crinoid debris, algae and shells, fragmentary D. septosa

7.5

Limestone, pale massive very fine-grained

24

Upper D. septosa Band: limestone, pale, with some crinoidal lenses, P. murchisoni and a few large brachiopods; fragmentary D. septosa at base

4

Limestone, pale massive fine-grained

8.75

The coral band near the top of this section was correlated by Shirley and Horsfield (1940, p. 276) with the Lithostrotion aff. maccoyanum band but is here considered to lie at a somewhat higher horizon. Wolfenden (1958, p. 873) noted the presence of oolitic limestones "near the Cyrtina band" in this vicinity.

To the south and south-east of Middle Hill the Bee Low Limestones, mostly above the horizon of the Lower Lava, form a broad plateau. Some 100 ft above the horizon of the Lower Lava a quarry (loc. 42) [SK 1299 8194] 265 yd S.W. of Rowter Farm shows 18 ft of pale finely crinoidal limestone with a 1-ft band 12 ft above the base, with L. junceum colonies in position of growth and Plicochonetes sp. buchianus group. The band lies at or near the horizon of the higher D. septosa band of Eldon Hill.

Between Perryfoot and Eldon Hill the back-reef facies, often showing inward dips, is usually well developed. The Bull Pit [SK 1065 8142], east of Perryfoot, shows 55 ft of off-white to grey massive fine-grained limestone with coarsely crinoidal lenses and some corals and brachiopods. The same facies, here showing variable gentle dips towards the reef, is exposed in a quarry (loc. 43) [SK 1125 8163] opposite Eldon Hill:

feet

(b) Limestone, pale weathering fine-grained, somewhat algal

(a) Limestone, pale grey-brown with very crinoidal bands with columnals up to 1 in diameter; some bands with limestone pebbles; evenly bedded in posts from 6 in to 1 ft 6 in except at base; large colony of L. junceum at 6 to 8 ft from base; other fauna includes P. murchisoni, abundant reef brachiopods and a specimen of Weberides sp.

24

Farther to the north-east a quarry (loc. 44) [SK 1208 8236] on the south side of Middle Hill also shows the back-reef facies:

feet

(b) Limestone, pale grey very poorly bedded, fine-grained, with very fossiliferous pockets; L. pauciradiale, abundant reef brachiopods including Acanthoplecta mesoloba, Antiquatonia antiquata,'Camarotoechia' sp., Dielasma hastatum, G. edelburgensis, Productus productus cf. hispidus, Pugnax sp.

16

(a) Limestone, pale grey finely crinoidal; L. martini, Athyris cf. expansa, Plicatifera cf. plicatilis

6

From the vicinity of Oxlow House the back-reef facies extends northwards along the limestone margin to Windy Knoll. Here a quarry [SK 1261 8300] shows 32 ft of limestone, much of it crinoidal and with some breccia; the lowest 9 ft are very fossiliferous, with reef brachiopods and Davidsonina septosa. The top 6 ft of the limestone are impregnated by elaterite (see p. 308). The presence of Neptunian dykes at this locality has been noted on pp. 110–1. The beds with D. septosa were considered by Shirley and Horsfield (1940, p. 275) to be the lower of the two D. septosa bands of Eldon Hill, which is here correlated with the Upper D. septosa Band.

Castleton

To the west of Treak Cliff and in the Winnats gorge the back-reef facies is little developed or absent. The Bee Low Limestones in this area show their normal lithology, being pale, massive and fine-grained. In the Winnats a 1-ft band with sporadic D. septosa is developed [SK 1344 8264] at a horizon some 170 ft below that of the Lower Lava. The same fossil occurs sporadically in the succeeding 60 ft of strata. The band has been correlated by Wolfenden (1958, pp. 873–4) with the 'Cyrtina band' (i.e. the Upper D. septosa Band), but all the occurrences noted here appear to lie below this horizon.

To the south of Castleton the section in Cave Dale shows the most complete development of the Bee Low Limestones. The lowest beds are in the back-reef fades [SK 149 825] just south-east of Peveril Castle; these show relatively strong inward dips near the reef margin but are usually less crinoidal than the back-reef facies near Eldon Hill. A fauna of reef brachiopods is sparsely developed in these beds in places. The extent of the back-reef facies is shown on (Plate 11).

Some 100 ft of Bee Low Limestones of normal facies are present beneath the Lower Lava in Cave Dale.

The Lower Lava, absent over much of the northern outcrops, reappears locally in Cave Dale and continues westwards from thence to near Hurdlow Barn. In Cave Dale it is up to 25 ft thick and shows its normal amygdaloidal character. The Lower Lava thins rapidly northwards and disappears on the east side of Cave Dale but has been proved by boreholes to extend eastwards for a short distance (see (Plate 4)). As the lava disappears its place is taken by the Pindale Tuff described by Eden and others (1964, pp. 76–8; see p. 61 of this account). The disappearance of the Lower Lava was attributed by Shirley and Horsfield (1940, pp. 275–6 and 287) to its being cut out by an unconformity at the base of the "Miller's Dale Beds". This explanation is not accepted here as, although minor non-sequences are frequent near the reef margin, there seems no need to postulate anything other than the normal dying out of a flow, frequently observed in the district. The L. aff. maccoyanum band at the base of the "Miller's Dale Beds", on which the above authors' conclusion was based, appears to be patchily developed and is difficult to trace laterally.

In Cave Dale two sections show the beds above the Lower Lava. The first (loc. 45) [SK 1475 8215] 0.5 mile S.S.W. of Castleton church is as follows:

feet

(h) Limestone, pale massive fine-grained

16

(g) Clay parting, thin, on marked bedding-plane

(f) Limestone, pale, with finely crinoidal patches and bands; some irregular shell-debris in coarser patches

3.25

(e) Limestone, pale fine-grained; irregular fracture

5.25

(d) Limestone, granular, finely crinoidal and oolitic

3.25

(c) Tuff, pale brown gritty-textured, soft weathered

0 to 1.5

(b) Limestone, pale; L. cf. aranea at 4.5 ft from top

about 28

(a) Not exposed

about 11

Top of Lower Lava

The coral band does not appear to persist laterally.

The second section [SK 1489 8219] shows a full development of the beds between the lava and the Monsal Dale Beds:

feet

Monsal Dale Beds

Limestone, pale massive

45

Limestone, granular crinoidal

4

Not exposed

0.75

Limestone, cross-bedded, granular crinoidal

1

Limestone, pale well-bedded fine-grained

28

Not exposed about

5

Lava, part amygdaloidal

11

Not exposed

5

Lava

In the higher part of Cave Dale much of the beds above the Lower Lava are exposed. Near the top and some 60 ft below the base of the Monsal Dale Beds the following section (loc. 46) [SK 1416 8178] is exposed:

feet

(d) Limestone, off-white finely bioelastic

0.5

(c) Limestone, pale grey

7.5

(b) Limestone, as above; Saccamminopsis sp., L. junceum and brachiopods

0.5

(a) Limestone, pale grey

6

These beds lie some 60 ft below the base of D2 and the fossil band would thus appear to be at or near the horizon of the coral band of Pin Dale (see below).

On Michill Bank the upper part of the Bee Low Limestones has been proved extensively. Borehole AF 4See also (Plate 4). Cores examined by Dr. D. V. Frost; record published by permission of Messrs. Earle Limited. [SK 1476 8188], showed the following succession:

Thickness

Depth

feet

inches

feet

inches

Monsal Dale Beds, (see p. 72)

154

6

Limestone, mostly pale grey fine-grained, oolitic in places

78

9

233

3

Limestone, grey crinoidal

2

11

236

2

Tuff, pale greyish green

4

236

6

Limestone, pale grey fine-grained with some pyrite and calcite veining below 241 ft

15

10

252

4

Tuff, pale grey-green with calcite veining

9

253

1

Limestone, pale grey fine-grained; with some nodules of pale chert; partly oolitic towards base

16

11

270

0

A fuller development of the Pindale Tuff has been proved by other boreholes in the area (see (Plate 4)). The thin tuff at a slightly higher horizon is at about the position of that occurring above the Lower Lava in Cave Dale.

Pin Dale and Earle's Quarry

In this area the most important section is that in Pindale Quarry (loc. 47) [SK 1594 8231]:

feet

Monsal Dale Beds (see p. 72)

(f) Limestone, pale grey massive, bioclastic and part crinoidal; a 1-ft coral band 4.5 ft from base with Caninia cf. densa [of Hudson and Cotton], C. cf. buxtonensis, D. bourtonense φ, L. cf. aranea, L. portlocki, P. murchisoni

37

(e) Limestone, pale grey thin-bedded (beds from 9 in to 2 ft 6 in) fined-grained, with some clay partings

17

(d) Not exposed (quarry floor) about

6

(c) Limestone, pale crinoidal, with a little pale nodular chert

5

(b) Clay parting 1 in

(a) Limestone, pale fine-grained, with some fine crinoid debris, nodular pale chert

18

Certain marginal features of the succession and the lateral passage to apron-reef are discussed on p. 108. The presence of chert in the D1 limestones in this section is remarkable in view of its total absence in beds of this age elsewhere in north Derbyshire. The coral band is nearer to the top of D1 than stated by Eden and others (1964, p. 78) but this is due in part to the placing of dark beds below the Lower Girvanella Band in D2 in this account.

In Earle's Quarry the uppermost D1 limestones have been extensively worked on the Lower Bench. Near the crusher house [SK 1612 8196] some 20 ft of massive grey limestones are exposed. Eden and others (ibid., p. 79) described these beds as having a maximum thickness of 53 ft in the quarry area. These beds overlie a group of darker grey limestones and overstep these in the vicinity of the tuff mound (see below) only some 10 ft of D1 beds crossing the axis of the mound.

The Pindale Tuff was formerly seen in Earle's Quarry where it occurred as a cone with dips up to 30° on the flanks and reached to a height of 70 ft (Shirley and Horsfield 1940, p. 282). This cone is now obscured by tip but extensive drilling has shown the widespread nature of the tuff beneath the quarry area and also the presence of a second cone, lying to the north-west of the first. The borehole records are summarized in (Plate 5), which also shows generalized isopachs on the tuff. To the east of the quarry area the Pindale Tuff is represented in attenuated form in a cutting (see p. 109) within the reef-belt.

Monsal Dale Group (D2)

Monsal Dale Beds below Upper Miller's Dale Lava

Near the southern margin of the district a thin development of dark limestone appears to be present locally beneath the Upper Lava, though exposures are lacking. These beds are in the position of the Station Quarry Beds of Miller's Dale (Cope 1937, p. 180); their presence is inferred from the topography, from debris on the outcrop, and from the relationships of the Station Quarry Beds to the Upper Lava on Hammerton Hill (One-inch Sheet 111) south of the present district. The Station Quarry Beds are of very limited extent within the Chapel en le Frith district, being faulted off near the junction of Tideswell Dale and Litton Dale and not developed again to the north of this point. They are included with the Monsal Dale Beds on the one-inch map. The examination of cutting samples from the Litton Dale Borehole [SK 1599 7498] (see also p. 55) is interpreted as showing the presence of pale grey and black limestones beneath the Upper Lava, between the depths of 8 and 14.5 ft. In view of this thin development the Station Quarry Beds may be expected to disappear at depth only a short distance north of the borehole.

Upper Miller's Dale Lava
Wormhill Moor

In this area the Upper Lava crops out around the base of an outlier of Monsal Dale Beds forming high ground between Bole Hill and Withered Low [SK 100 765]. The lava shows its maximum thickness of 100 ft at the southern edge of the outlier, but thins northwards to 10 to 15 ft on Withered Low. The southern outcrops are unusual in that two beds of limestone are present within the lava; the lower some 30 ft from the base near Hargatewall and the higher, near the top, at Bole Hill. The limestone bands are interesting in view of the difficulty in distinguishing different flows within the outcrops of both Upper Lava and Lower Lava.

Exposures showing the normal amygdaloidal character of the lava are lacking in this area though yellow clay or fragments of weathered lava have been observed in places. At Bole Hill [SK 1059 7543] a roadside exposure shows dark crystalline non-vesicular basalt interpreted, as in the case of similar features in the Lower Lava (see p. 52), as the central part of a flow.

Tideswell Dale to Old Moor

The Upper Lava crops out on the high ground east of Tideswell Dale though a short distance beyond the southern margin of the district it fails. The rapid dying out of the lava in Litton railway-cutting (One-inch Sheet 111) has been described by Cope (1937, p. 179). Near the junction of Tideswell Dale and Litton Dale [SK 1563 7484] the lava shows its normal amygdaloidal character. In this vicinity it appears to be at least 60 ft thick but it must thin rapidly eastwards for the Litton Dale Borehole [SK 1599 7498], starting near the top, showed only 8 ft of weathered lava (purple to grey clay).

The Upper Lava is faulted off at the junction of Tideswell Dale and Litton Dale but it reappears west of Tideswell though it is there rather thin and not exposed. Between Crossgate and Wall Cliff the only exposure [SK 1367 7676], near Wheston, shows dark crystalline non-vesicular lava. On the southwest side of Wall Cliff the lava thins and disappears, though it reappears farther to the east, where a small thickness of Upper Lava is present locally passing southwards into tuff. This was described by Arnold-Bemrose (1907, p. 253), as the Brook-Bottom Tuff. A section [SK 1438 7709] north-west of Highfield House shows amygdaloidal lava 1.5 ft on banded dark calcareous tuff. The tuff thickens southwards and another section [SK 1444 7702] shows 10 ft of dark banded calcareous tuff with dark cognate lapilli up to 0.75 in diameter. The tuff disappears rapidly eastwards across the valley and the lava is interpreted as having been cut out by strike-faulting between Wall Cliff and White Rake. On the south side of White Rake the lava is again present and 11 ft of it, deeply weathered, were exposed in an open working [SK 1480 7810] on the vein.

To the north of White Rake exposures of the Upper Lava are rare, though an excavation made in a sink-hole near the base of the bed [SK 1388 7909] near The Holmes showed yellow clay with blocks of tuffaceous limestone up to 1 ft across at from 7 to 15 ft below ground level. The weathered state of the exposure makes it uncertain whether these beds represent a bedded tuff at the base of the flow or whether the tuff and limestone were dragged up by the flow and incorporated in it. To the north of this locality the Upper Lava is little seen. At Cop Round the outcrop is conspicuous as a 'slack' beneath the scarp of the lowest part of the Monsal Dale Beds. The thickness here is about 20 ft. The lava is last seen on the north wall of an open working on the vein-plexus of Oxlow Rake [SK 1350 8087]. This shows the lowest part of the Upper Lava, much weathered, as 4.5 ft of yellow clay, resting on limestone. Traced northwards from here, the lava thins rapidly and disappears.

Lower Monsal Dale Beds
Dove Holes

At Dove Holes (Figure 7) the Lower Monsal Dale Beds are present between Peak House and Near Ridgeclose. The best section, in Victory Quarry (loc. 30) top at [SK 0748 7702], continues that described on p. 54:

feet

inches

(y) Limestone, grey-white massive fine-grained to finely granular, some fine crinoid debris; colonies of Syringopora sp. at base

10

0

(x) Limestone, very fine-grained, calcilutite in places, shelly with Gigantoproductus dentifer, G. edelburgensis [juv.], Linoproductus sp. hemisphaericus group

4

7

(w) Limestone, pale grey massive fine-grained

4

0

(v) Limestone, grey-white fine-grained, with some fine crinoid and shell debris; more shelly in upper half

4

5

(u) Not exposed about

3

0

(t) Limestone, off-white massive fine-grained; somewhat shelly in top 10 ft, scattered shells below; coral band 1.5 ft at 10.5 ft down and band with sporadic corals 3.5 ft thick 2 ft from base; Caninia benburbensis, Dibunophyllum bipartitum, Diphyphyllum lateseptatum, Lithostrotion junceum, L. martini, G. dentifer, G. edelburgensis [juv.], Linoproductus sp. hemisphaericus group

25

0

(s) Limestone, medium grey massive fine-grained, somewhat crinoidal; Antiquatonia hindi wettonensis, 'Brachythyris' planicostata, G. dentifer, G. edelburgensis, L. sp. hemisphaericus group (bed absent on south side of quarry)

0 to 3

0

(r) Limestone, dark thin-bedded; irregular thin clay wayboard at base

5

0

(q) Limestone, grey massive cherty; coral in position of growth at 4 ft up

7

0

(p) Limestone, dark massive, with scattered chert

5

0

(o) Limestone, dark grey to grey-brown massive fine-grained; Dibunophyllum sp. [juv.], Lithostrotion?, A. insculpta, G. crassiventer, Productus sp.

6

0

(n) Clay parting

2.5

(m) ' Limestone, grey to dark grey, bituminous in places, sometimes finely crinoidal, thin-bedded; a 6-in band with Saccamminopsis sp. 3 ft above base

6

2

(l) Limestone, grey finely crinoidal and slightly oolitic; some shells

1

2

(k) Limestone, grey finely granular; darker in upper 4 ft 4 in; slight erosion surface at base

6

6

Miller's Dale Beds

The shell bed at the top of the section is traceable for some 400 yd northwards from this locality, cropping out again [SK 0748 7734] 110 yd N. of Lower Bibbington. The dark limestones at the base of the Monsal Dale Beds are a feature of the whole of the outcrop at Dove Holes.

The section [SK 0799 7828] (loc. 33) along the old Peak Forest railway at Dove Holes shows the lowest part of the Monsal Dale Beds:

feet

(f) Limestone, grey-brown finely granular, crinoidal, weathering dark; slight erosion surface at base

3

(e) Limestone, pale brown massive fine-grained; fragmentary productoids, L. portlocki

25

(d) Limestone, dark very fine-grained, 'hackly' fracture; corals in top 1 ft, L. junceum, L. martini, P. murchisoni; abundant Saccamminopsis fusulinaformis from 4.5 ft to top of bed; also 'Brachythyris' planicostata and Semiplanus sp. latissimus group

12

(c) Limestone, dark bituminous, thin-bedded with shaly partings

12.5 ft to 15

(b) Limestone, dark grey massive abundant 'Girvanella'nodules in lowest 1.75 ft; sharp base

4

Miller's Dale Beds (see p. 54)

When traced northwards the uppermost dark limestones of this section and the lowest 8 ft or so of the overlying beds are replaced laterally by a knoll-reef (loc. 48) [SK 0797 7866] west of Near Ridgeclose; this shows up to 24 ft of pale grey often coarsely crinoidal limestone with a rather poor fauna, including L. martini, A. hindi wettonensis, G. crassiventer and G. dentifer. To the north of the knoll a coral band (loc. 49), probably in the position of that at the top of bed (d) of locality 33, yields Diphyphyllum lateseptatum and L. martini. The overlying limestones yield Gigantoproductus giganteus cf. crassus and G. crassiventer.

Barmoor Clough and Sparrow Pit

This outcrop (Figure 7) is nearly continuous with that of Dove Holes and shows a similar development of dark limestones, up to about 20 ft in thickness, at the base. The higher beds are pale, well-bedded limestones with two knoll-reefs. The dark beds are well seen in small exposures near the road junction at Barmoor Clough. A short distance to the east a section (loc. 50) [SK 0789 7949] at the limestone-shale boundary, is as follows:

feet

inches

(e) Shale, fissile, black; decalcified mudstone at base (referred to Edale Shales)

2

0

(d) Limestone, dark grey

10

(c) Not exposed

2

0

(b) Mudstone, dark grey passing down into platy shale

2

0

(a) Limestone, medium to dark grey; Martinia cf. glabra, Rugosochonetes sp., Caneyelia membranacea, Posidonia corrugata, Rineceras sp., Girtyoceras sp.

2

6

The occurrence of the P1 goniatite Girtyoceras shows the presence of a small area of beds of basin facies at this locality.

The old Barmoor Clough Quarry, east of Bennetston Hall, shows the top of the dark limestones and the succeeding beds; a knoll-reef, developed in the latter on the eastern side of the quarry, complicates the section. At the northern end of the quarryNow filled in.(loc. 51) [SK 0881 7988] the sequence is as follows:

feet

inches

(i) Limestone, very pale grey granular with crinoidal bands near top; at 6 ft from top, productoid fragments including Productus sp.

16

0

(h) Limestone, pale grey massive; top 3 ft near-white with Rotiphyllum costatum, Zaphrentires enniskilleni, Gigantoproductus crassiventer, G. dentifer, G. edelburgensis, Productus productus hispidus

10

0

(g) Shale

0 to0.5

(f) Limestone, grey, crinoidal in lower half; D. lateseptatum, Lithostrotion pauciradiale, Lonsdaleia floriformis laticlavia

4

3

(e) Shale, hard calcareous, with shell debris

0.5 in to 1

(d) Limestone, grey crystalline, somewhat crinoidal; Diphyphyllum furcatum, Lithostrotion portlocki, Gigantoproductus giganteus

1

9

(c) Limestone, pale finely granular; shell fragments

3

4

(b) Not exposed

6

0

(a) Limestone, dark (top only seen)

The highest beds form part of the western margin of the knoll-reef. In the middle part of the quarry a non-sequence develops within bed (h) and results in the cutting out of 7 ft of the underlying beds. Another section of the knoll nearby [SK 0878 7977] shows 10 ft of pale grey strongly banded reef-limestones, the top 4 ft conglomeratic, resting on grey normal-bedded cherty limestones, 3.25 ft. A small quarry (loc. 52) [SK 0890 7981] at the eastern end of the knoll, shows the following section:

feet

inches

(c) Limestone, grey-brown coarsely granular; Cyathaxonia rushiana, Cladodus sp.

10

(b) Limestone-breccia, pale brown; Caninia sp. subibicina group

1

0

(a) Limestone, grey-brown granular

2

6

The presence of the fish Cladodus suggests that this is the locality from which Jackson (1908, p. 309) recorded "Psammodus rugosus" and "Psephodus magnus".

The greatest thickness of Lower Monsal Dale Beds in the vicinity is some 0.5 mile south of Sparrow Pit where it is about 200 ft. The highest beds are exposed in a small quarry [SK 0900 8025] some 0.33 mile S. of Sparrow Pit: grey-brown thin-bedded cherty limestone, somewhat crinoidal and shelly, algae investing shell debris in top 3.5 ft, on pale grey-brown well-bedded granular oolitic limestone, slightly crinoidal, 3.5 ft. The position of the algal horizon compares with the average position of the Upper Girvanella Band (125 ft above base of Monsal Dale Beds at Pin Dale and 300 ft up in Cressbrook Dale) with which it is tentatively correlated.

To the north of the last locality the thickness of the exposed Lower Monsal Dale Beds decreases steadily. The lower, dark beds persist but the higher strata pass laterally into crinoidal knoll-reef limestones forming the crest of a small hill at Sparrow Pit. An exposure [SK 0915 8082] 175 yd N.E. of the crossroads at Sparrow Pit shows grey-brown poorly bedded shelly reef limestone 5 ft, on dark bituminous crinoidal limestone. A little to the north [SK 0918 8098] the Monsal Dale Beds are cut out by the unconformity at the base of the Namurian.

Wormhill Moor

In this area the lowest 50 ft of the Monsal Dale Beds forms an outlier. Here pale limestones usually overlie the Upper Lava though in one place [SK 1040 7624] a foot of dark grey limestone is exposed in this position.

A quarry (loc. 53) [SK 1059 7552] on Bole Hill provides the only good section:

feet

(f) Limestone, pale crinoidal

3

(e) Limestone, off-white fine-grained, shelly; Striatifera striata

1.25

(d) Limestone, off-white massive slightly crinoidal; Lithostrotion decipiens, G. sp. edelburgensis group, Linoproductus sp. hemisphaericus group

14.5

(c) Limestone, off-white fine-grained, sporadic shells

10 in to 1

(b) Limestone, off-white massive, slightly crinoidal and oolitic

6.75

(a) Limestone, pale grey-brown finely granular, many small shells including Athyris expansa

2.25

Cressbrook Dale

This dale provides the best, though not continuous, section of the beds below the Litton Tuff in the southern part of the area. The lowest beds consist of dark, thin-bedded cherty limestones. These strata are generally rather poorly exposed. Shirley and Horsfield (1945, p. 297) give the thickness as 80 ft, which is accepted here. The main outcrop lies south of where White Rake crosses Cressbrook Dale and the dark beds also occur as a faulted inlier in the lower part of Tansley Dale and for some 300 yd from its confluence with the larger dale. Shirley and Horsfield also noted the presence of Saccamminopsis sp. at two horizons in the dark limestones, the lower at the base being the better exposed, while the upper band "about 50 feet higher" was known only at the northern end of Litton Frith. The lower band was noted in an exposure by a footpath [SK 1734 7435] on the eastern side of the dale. The section (loc. 54) [SK 1716 7437] at Litton Frith shows the lowest Dart of the Monsal Dale Beds:

feet

(k) Limestone, dark fine-grained; Saccamminopsis in uppermost 6 in

2

(j) Limestone, medium to pale grey fine-grained, with some chert about

2

(i) Limestone, dark fine-grained

2

(h) Not exposed

8

(g) Limestone, dark grey, with some fine crinoid debris; Saccamminopsis in uppermost 2 in

3.5

(f) Not exposed about

1.5

(e) Limestone, dark to medium grey, thin-bedded, with some chert; L. junceum 1.5 ft from base

6

(d) Limestone, dark fine-grained with a little fine crinoid debris; a silicified colony of L. junceum 3 ft from base

8

(c) Not exposed

3

(b) Limestone, dark grey finely crinoidal noidal

2.5

(a) Limestone, dark grey with scattered shell debris and fine crinoid debris; Saccamminopsis throughout

6.75

Miller's Dale Beds

This section shows both the lower and higher Saccamminopsis horizons noted by Shirley and Horsfield, the latter 45 ft from the base of the Monsal Dale Beds. There is also a similar band 39 ft from the base. The succeeding beds, some 120 ft thick, consist of pale chert-free limestones. Some 22 ft above the base of the pale beds the shell bed (loc. 55c), noted by Shirley and Horsfield (1945, p. 297) as containing Striatifera striata, can be traced from near the southern margin of the district along both sides of the dale. This fossil has not been confirmed in the shell bed though it has been found just above (loc. 55d).

Near Peter's Stone a thin lava, whose presence was noted by Arnold-Bemrose (1907, p. 255), is present for a distance of some 400 yd along the dale sides close beneath the Litton Tuff. The most complete section (loc. 55) of the Lower Monsal Dale Beds hereabouts [SK 1725 7490] about 0.5 mile S.S.W. of Littonfields, is as follows:

feet

(q) Litton Tuff (see p. 75)

42

(p) Not exposed (features suggest limestone)

28

(o) Limestone, pale grey; shell debris

1

(n) Not exposed (limestone)

2

(m) Not exposed (outcrop of lava)

6

(l) Limestone, pale grey massive; a few Gigantoproductus sp.

8

(k) Limestone, pale grey crinoidal; a few rolled shells

1.5

(j) Limestone, pale grey massive; some crinoid debris

21

(i) Not exposed

5

(h) Limestone, pale crinoidal

2

(g) Not exposed

6

(f) Limestone, pale grey, crinoidal in part

5

(e) Not exposed

10

(d) Limestone, pale grey very crinoidal in places, part shelly; Striatifera striata

16

(c) Limestone, pale grey crinoidal, shelly in top 1 ft, less so below (shell bed of text); Gigantoproductus sp. cf. semiglobosus

4

(b) Limestone, grey to pale grey massive crinoidal; a little chert in lowest 4 ft

22

(a) Limestone, dark grey below, grey above, thin-bedded, chert lenses (upper part of lower, dark limestones of text)

30

The following section [SK 1729 7506] supplements that given above so far as the relationship of the lava to the Litton Tuff is concerned:

feet

Litton Tuff

Limestone, dark to medium grey poorly bedded though with some thin argillaceous limestone partings; some shell debris

7

Not exposed

10

Lava, dark amygdaloidal

seen 10

Shirley and Horsfield (1945, p. 295) show the lava as reaching a thickness of 20 ft. In that part of Cressbrook Dale south of Tansley Dale the lava is absent. A section here [SK 1754 7465], starting some 75 ft above the horizon of the shell bed, is as follows:

feet

Litton Tuff (not exposed)

Limestone, grey coarsely crinoidal; some shells

5

Limestone, grey shelly, rather rubbly weathering

3

Limestone, grey; occasional shells

15

Not exposed

75

Shell bed (bed c of loc. 55, p. 67)

Litton, Tideswell and Brook Bottom

In this area the beds below the Litton Tuff are in general poorly exposed. The dark beds at the base are present on the southern edge of the district south-west of Litton, but die out rapidly northwards. Debris of dark limestone with corals was seen [SK 1582 7443] in this area. In Litton Dale the dark limestones are apparently absent but they reappear in the northern part of Tideswell village (see below). As in Cressbrook Dale the overlying beds consist of pale and apparently everywhere non-cherty limestones though these are seen only in scattered small exposures. Some 50 ft above the Upper Lava a coral band is exposed (loc. 56) [SK 1584 7468] in Litton Dale; this consists of a 9-in coral-bearing bed below and, 3 ft higher, a similar 12-in bed. Both beds yield L. junceum. The strata above are seen in small exposures of predominantly pale crinoidal limestones south-east of Litton Dale e.g. [SK 1658 7497]. Between Litton and Tideswell some darker beds make their appearance in the middle of the Lower Monsal Dale Beds; these also are only seen in small exposures e.g. [SK 1585 7522].

The upper part of the Lower Monsal Dale Beds was passed through in the Littonfields BoreholeRecord from examination of cutting samples by Professor F. W. Shotton. [SK 1751 7595]:

Thickness

Depth

feet

feet

Upper Monsal Dale Beds (see pp. 84–5)

249

Mudstone

0.5

249.5

Limestone

20

269.5

Litton Tuff (see also p. 75)

10.5

280

Limestone, tuffaceous, with pyrite

3

283

Limestone, pale grey

4

287

Limestone, black banded crinoidal

3

290

Limestone, pale grey above, white below

19

309

Tuff, pale green

2

311

Cressbrook Dale Lava; basalt, amygdaloidal with a probable tuff parting at 389 ft

109

420

Limestone, pale grey

45.5

465.5

Mudstone, dark grey

2.5

468

Limestone, pale grey

12

480

To the west of the Tideswell–Brook Bottom valley beds low in the D2 Zone crop out in an elongated tract. The nature of the lowest beds is uncertain south-west of Tideswell though 3 ft of pale limestone were seen 30 ft above the base [SK 1461 7556] near Summer Cross. On the western edge of the outcrop, dark beds make their appearance near Crossgate [SK 1435 7597] where 1.5 ft of dark limestone are present 5 ft above the Upper Lava. A section (loc. 57) [SK 1425 7610] near Crossgate shows the junction of the dark limestones and overlying beds:

feet

(d) Limestone, fine-grained grey-brown; 5-in band at 2 ft from base bearing L. junceum? and Gigantoproductus sp.

4

(c) Limestone, grey-brown bioclastic ; abundant bryozoa and shell fragments

0.25

(b) Limestone, dark grey-brown thin-bedded fine-grained

4

(a) Not exposed

12

Upper Lava

To the north of the last locality the dark limestones may be traced as far as Water Lane [SK 1384 7680], north of which they disappear, probably by lateral passage. The beds overlying the dark limestones are exposed in a small quarry (loc. 58) [SK 1383 7669]:

feet

(b) Limestone, pale thinly bedded; Caninia juddi, L. junceum, L. martini, abundant brachiopods including A. insculpta, G. edelburgensis, G. sp. cf. moderatus, Monograptus sp. papilionaceus group, P. productus hispidus

8

(a) Limestone, medium to dark grey

2.5

Higher beds, grey to pale grey limestones e.g. [SK 1473 7598] and pale crinoidal limestones e.g. [SK 1448 7631], both chert-free, form a marked dip-slope between the last described exposures and the lip of the Brook Bottom valley.

In Brook Bottom the dark limestones at the base of the Monsal Dale Beds are traceable from the outskirts of Tideswell [SK 1501 7604] to a point [SK 1449 7717] a little north of Highfield House where they pass laterally into pale limestones. The best section (loc. 59) [SK 1473 7638] is as follows:

(k) Limestone, buff, with scattered crinoid and shell debris in places; shell band at top with G. edelburgensis, Pugilis pugilis

16

(j) Limestone, dark to medium grey fine-grained shelly; G. edelburgensis, G. sp. cf. bisati, Productusproductus hispidus

2.25

(i) Limestone, dark grey fme-grained, with a little chert; gastropods at 7 ft above base; G. sp. cf. bisati at top

13.25

(h) Not exposed

2

(g) Limestone, dark fine-grained cherty, in beds up to 1 ft: G. sp. cf. moderatus

8

(f) Limestone, dark, fine-grained, poorly exposed

12

(e) Not exposed

3

(d) Limestone, dark grey bituminous, in beds up to 9 in; thin partings of bituminous shale

2.5

(c) Not exposed

1.25

(b) Calcilutite, pale brown finely banded; some wavy banding

1.5

(a) Limestone, grey-brown fine-grained

2

The position of the lowest 3.5 ft of beds in this section is in some doubt, but these have been referred on lithological grounds to the pale facies of the Lower Monsal Dale Beds; they are, perhaps, the first indication of the southward failure of the dark beds at Tideswell which has already been noted (p. 69). Farther north, the dark beds thin; a shaft [SK 1454 7663] to the sough at the eastern end of Edge Rake, which started near the top of these, proved only 20 ft of limestones overlying 'toadstone'. To the south-west of Highfield House the dark beds bear a Saccamminopsis band at their top [between 1448 7673 and 1445 7683]. This band has also been found [SK 1450 7703] north of Highfield House in the following section (loc. 60):

feet

(b) Limestone, grey

2.5

(a) Limestone, dark grey thinbedded; Saccamminopsis sp. abundant in lowest 3 ft and sporadic above

6

To the south of Wall Cliff, a section [SK 1377 7723] shows pale beds close above the Upper Lava:

feet

Limestone, pale finely crinoidal, with fine shell debris, some invested with ?algae

1

Limestone, pale fine-grained, with a 7-in silicified lens

4.25

Wall Cliff to The Holmes

Between Wall Cliff and White Rake the lowest part of the Lower Monsal Dale Beds is apparently cut out by a strike fault. Some exposures of higher beds close beneath the Litton Tuff are present south of Tides Low. These show grey limestones e.g. [SK 1503 7758] and grey to pale grey crinoidal limestones e.g. [SK 1488 7754] both non-cherty. Open workings in White Rake show the following section (loc. 61) [SK 1474 7814] in the north wall:

feet

(d) Limestone, pale fine-grained; small shells

2.5

(c) Limestone, pale to medium grey, fine-grained; sparse Saccamminopsis sp.

7.25

(b) Limestone, pale to medium grey thin-bedded fine-grained

3.5

(a) Limestone, off-white to pale grey massive fine-grained to finely granular

23

The base of the section lies some 10 ft above the Upper Lava. Immediately to the northwest of this locality a parting of grey clay, possibly weathered tuff, perhaps some 3 to 5 ft in thickness, has been proved in auger holes. The base lies some 15 ft above the Upper Lava and the clay bed extends laterally for some 250 yd.

Between Maiden Rake and Shuttle Rake the lowest Monsal Dale Beds form a strong scarp above the Upper Lava. A section of these beds (loc. 62) [SK 1436 7860] west-northwest of Bushyheath House is as follows:

feet

(d) Limestone, medium to pale grey thin-bedded slightly crinoidal; L. junceum, L. maccoyanum, G. dentifer, Monograptus sp. papilionaceus group, Striatifera striata and gastropods; slight erosion surface at base

15

(c) Limestone, pale massive finely oolitic

13

(b) Limestone, pale grey very crinoidal with some shells

3

(a) Limestone, grey fine-grained, with a small included mass of darker limestone (7 in x 1 in)

2.5

Near Shuttle Rake a small exposure [SK 1416 7903] shows 1 ft of dark limestone some 20 ft above the Upper Lava but there is sufficient exposure in the vicinity to show that this is exceptional. Higher beds, seen in a number of exposures north of Bushyheath House, consist of pale grey limestones, non-cherty and often massive.

Near The Holmes the Lower Monsal Dale Beds appear to be only some 100 ft in thickness. A section (loc. 63) near the base [SK 1403 7918] is as follows:

feet

(d) Limestone, pale crinoidal; C. benburbensis, P. murchisoni, Linoproductus sp. hemisphaericus group

9

(c) Not exposed

2

(b) Limestone, massive pale crinoidal

7

(a) Limestone, medium to dark grey fine-grained

2.5

A section (loc. 64) starting some 50 ft above the Upper Lava exposed nearby [SK 1411 7920] shows 6 ft of pale grey massive limestone with a 1.5 ft band 3 ft from base, bearing Dielasma hastatum, L. sp. hemisphaerieus group and Productus productus.

Bradwell Moor

At Cop Round the basal Monsal Dale Beds form a conspicuous scarp and are well exposed. Here [SK 1302 8002] 11 ft of near-white fine-grained limestones crop out close above the Upper Lava. Another section of the lowest beds (loc. 65) [SK 1336 8060] is: grey-brown finely bioclastic and oolitic limestone with a colony of L. maccoyanum 1.25ft, grey-brown fine-grained limestone 1.5 ft, on grey-brown finely No-elastic and oolitic limestone 2 ft.

To the north of Dirtlow Rake the recognition of the Upper Girvanella Band in boreholes and surface exposures has made the stratigraphical relations of the Lower Monsal Dale Beds clearer than in the part of Bradwell Moor to the south. The Lower Girvanella Band is probably represented in a small exposure [SK 1417 8149] showing grey-brown finely bioclastic limestone 5 ft thick with algae at 2 ft from base. The section on the south-east side of Cave Dale top of section [SK 1493 8218], continuing that given on p. 60, shows the lowest beds:

feet

Limestone, pale grey-brown finely crinoidal cherty

4

Not exposed

6

Limestone, grey, crinoidal at top

8.5

Limestone, variegated dark and pale, thin-bedded, finely crinoidal at top and coarsely so at base

6

Bee Low Limestones

Farther east, beds near the base of the Monsal Dale Beds are also seen just north of Dirtlow Rake [SK 1526 8211]: pale crinoidal limestone, coarse in lower half, 3 ft 10 in, on pale massive limestone with a little crinoid debris, finely banded and sorted towards top, 10 ft 6 in. The only other exposures worthy of note in this area lie a little below the Upper Girvanella Band. These include a small knoll-reef (loc. 66) [SK 1440 8149] showing 10 ft of pale massive fine-grained limestone with some calcite veining; the fauna includes Lithostrotion decipiens, a large colony of L. junceum and brachiopods including Eomarginifera tissingtonensis cambriensis. The knoll is apparently on the horizon of the "third pale coloured calcirudite" noted by Eden and others (1964, p. 85) close below the Upper Girvanella Band in Earle's Quarry. A nearby exposure [SK 1436 8147] of beds just underlying the knoll, shows dark bituminous limestone 2 ft, on pale to medium greylimestone with shells and corals, some silicified, 1.25 ft. Dark beds in this position are not frequent in the Lower Monsal Dale Beds but have been noted (ibid., p. 80) in Earle's Quarry No. 4 Borehole.

The most complete section of the Lower Monsal Dale Beds in the area north of Dirtlow Rake is provided by Messrs. Earle's Borehole AF 4See also (Plate 4). Cores examined by Dr. D. V. Frost.(loc. 67):

Thickness

Depth

feet

inches

feet

inches

Soil, etc.

1

8

1

8

Upper Girvanella Band: limestone, dark, thin-bedded, with (b) 'Girvanella' at 4 ft 6 in to base

10

6

12

2

Limestone, grey-brown finely oolitic

2

10

15

0

Limestone, pale coarsely crinoidal

7

3

22

3

Limestone, grey-brown in top 4 ft, grey to dark grey below

10

3

32

6

Limestone, pale coarsely crinoidal; somewhat oolitic; a little chert

26

6

59

0

Limestone, grey-brown somewhat oolitic

3

4

62

4

Limestone, grey to dark grey cherty; (a)'Girvanella' ?

5

2

67

6

Limestone, pale grey-brown, oolitic in places

28

6

96

0

Limestone, grey to grey-brown partly oolitic, darker towards base; a little chert

32

0

128

0

Limestone, pale grey cherty

15

8

143

8

Limestone, grey to dark grey fine-grained, with dark partings (position of Lower Girvanella Band)

10

10

154

6

Bee Low Limestones (see p.61)

Pin Dale and Earle's Quarry, Hope

The Lower Monsal Dale Beds have been proved in a large number of boreholes by Messrs. Earle and are also well seen in Pindale Quarry and Earle's Quarry (see (Plate 5)). These beds show non-sequences at several horizons, more acute as the margin of the reef-belt is approached, and there is also much lateral variation within individual beds. The main features of the stratigraphy have been described by Eden and others (1964).

The section in Pindale Quarry (loc. 47) (Shirley and Horsfield 1940, pp. 284–6) shows much of the Lower Monsal Dale Beds (see also p. 61). The section refers, for the greater part, to the southern end of the quarry top at [SK 1581 8216] where the sequence is most complete. Most of the section, except for the lowest and some of the middle beds, is inaccessible and this part has been compiled from observation of the quarry face, from borehole recordsEarle's Quarry No. 7, see Eden and others (1964, pp. 114–6); Earle's Quarry No. 8. close behind the face and from the account by Eden and others (1964):

feet

(s) Limestone, pale very coarsely crinoidal shelly ("third calcirudite"); slight non-sequence at base

10

(r) Limestone, grey, slightly irregularly bedded, somewhat crinoidal

20

(q) Limestone, dark, thin-bedded cherty

3 to 7

(p) Limestone, grey and dark grey; large shells near base

9

(o) Limestone, pale; top 3 ft with abundant crinoid debris, some coarse, and fairly common large shells; less crinoidal and with scattered shells below ("second calcirudite") ; thickens in depression in bed below; non-sequence at base

9.5 to 20

(n) Limestone, dark grey; mainly crinoidal in lower half, passing into grey crinoidal limestone at south end of quarry

13

(m) Limestone, grey, shelly in upper half

4

(l) Limestone, dark crinoidal

2

(k) Limestone, pale crinoidal; some shells.

11

Unconformity (absent in south end of quarry)

(j) Limestone, dark crinoidal, uppermost 3 ft passing laterally into pale limestone at south end of quarry; some shells

6

(i) Limestone, grey to dark grey, somewhat crinoidal and shelly

7

(h) Lower Girvanella Band: limestone, dark thin-bedded cherty; 'Girvanella' (especially common at top)

9

(g) Limestone, dark thin-bedded crinoidal

6

The lowest item (g) appears to be a local development, probably filling a slight hollow in the underlying Bee Low Limestones, as it is not elsewhere developed. Beds (j-m) constitute the "first calcirudite" of Eden and others. The unconformity within the latter (noted by Shirley and Horsfield 1940, p. 284, fig. 1) cuts out all the lower D2 beds at the north end of the quarry. The overlying beds of the "first calcirudite" (k-m) pass northwards into pale shelly flat-reef limestones as the reef-belt is approached. Compared with the unconformity the two non-sequences noted are slight, the lower cutting out up to 3 ft of the underlying bed and the upper up to 1 ft.

To the east of the entrance to Pin Dale the lateral passage of beds low in the D2 sequence into apron-reef limestones (see p. 108) takes place at the crest of the slope above Upper Jack Bank Quarry. A little to the south the large excavation of Earle's Quarry again shows the base of the Monsal Dale Beds. A section (loc. 68) at the south-east end of Upper Jack Bank Quarry [SK 1620 8208] (Eden and others 1964, pp. 99, 105) shows the lowest beds:

feet

(b) Limestone, grey well-bedded; some shelly bands

6

(a) Lower Girvanella Band: limestone, dark thin-bedded with partings of dark shale; some shelly bands; 9-in band 3 ft from base, with abundant Girvanella stamina

6

Bee Low Limestones

The irregular nature of the Lower Girvanella Band is shown by its absence in a section (loc. 69) [SK 1620 8202] only 60 yd to the south:

feet

(d) Limestone, medium to pale grey massive

4

(c) Limestone, dark; Saccamminopsis sp.

2

(b) Limestone, dark grey coarsely crinoidal

2.25

(a) Limestone, dark thinly but irregularly bedded

2.25

Erosion surface

Bee Low Limestones

In the main quarry (loc. 70) the succession in the Lower Monsal Dale Beds has been described in detail by Eden and others (1964, pp. 81, 85) and may be summarized as follows:

feet

Base of dark limestones with Upper Girvanella Band

(g) Limestone, grey ("calcarenite") with some crinoidal bands; occasional shells; Middle Bench [SK 1592 8206] contains a 1-ft coral band, with base 5 ft from top, bearing Dibunophyllum bipartitum konincki and Diphyphyllum cf. lateseptatum

10 to 15

(f) Limestone, pale coarsely crinoidal and with rolled shell fragments ("third calcirudite")

about 10

(e) Limestone, grey below, rather dark ("dark calcarenite") in upper part near reef-belt but becoming grey away from it, fine-grained; in Middle Bench a non-sequence is present at the base of the dark limestones and cuts out up to 10 ft of the underlying beds; a band of large productoids is present in middle of subdivision

25 to 50

(d) Limestone, pale crinoidal ("second calcirudite"); in Middle Bench [SK 1608 8210] the top 3 ft is a flat reef with P. productus hispidus; away from reef-belt the lower part passes laterally into finer-grained beds ("pale calcarenite") and the upper into a rolled-shell bed

12

(c) Limestone, usually rather dark well-bedded ("calcarenite") with coarsely crinoidal bands and lenses; 8 ft below the top [SK 1609 8209] P. productus and P. productus hispidus

20 to 35

(b) Limestone, pale coarsely crinoidal "first calcirudite"); shelly; in eastern part of quarry the top few feet pass laterally into flat-reef limestones (back-reef); with breccia locally near reef-belt [SK 1613 8196] associated with a non-sequence in area of Middle Bench (cf. Pindale Quarry)

10 to 20

(a) Limestone, dark, with Lower Girvanella Band; some crinoidal bands

about 10

The above general succession is supplemented by the selected borehole records shown graphically in (Plate 5). In addition two sections in the lowest beds are worthy of note. The first (loc. 71) was measured by R. A. Eden in a small pillar [SK 1622 8191] (ibid., pp. 99, 105), left by quarrying adjacent to the tuff mound and now tipped over:

feet

(l) Limestone, pale very crinoidal; 1.5 ft shell bed at base

8

(k) Limestone, grey, mottled in part, fine grained; crinoidal bands and shelly bands

3

(j) Limestone, rather dark grey in lower part and paler above, fine-grained; some crinoidal debris

7

(i) Limestone, fine-grained dark; C. benburbensis, L. pauciradiale; 3 ft from base, Draffania sp., Girvanella sp.

4.5

(h) Clay parting, thin, on slight erosion surface

(g) Limestone, dark coarse-grained crinoidal

1

(f) Clay parting, thin, on erosion surface

(e) Limestone, grey, somewhat crinoidal

4

(d) Limestone, grey to dark grey, with crinoid debris in fine-grained matrix; some shells

6

(c) Limestone, dark, fine-grained, with clay partings

0.5

(b) Limestone, grey massive, somewhat crinoidal; some shells

6

(a) Clay, brown, with lenses of fine-grained dark shelly limestone

0.75

Bee Low Limestones

Beds (j-l) represent the "first calcirudite". The underlying beds are somewhat thicker than normal; it may be that, as has been suggested for the Pindale Quarry section, the two lowest beds fill a slight hollow in the underlying strata.

To the south-east of Wilson's Monument and the site of the tuff mound (see pp. 61–2) important unconformity is present at the horizon of the Upper Girvanella Band. This cuts out up to 30 ft of the underlying beds and is most acute in the vicinity of the tuff mound. The unconformity is attributed by Eden and others (ibid., p. 78) to later folding on the axis of the mound. This interpretation agrees with the relations in Monk's Dale where two vents are present on the line of a local sharp fold (see p. 323).

The easternmost section (loc. 72) in Earle's Quarry [SK 1643 8189] shows the lowest part of the Monsal Dale Beds adjacent to the reef-belt:

feet

(j) Limestone, pale coarsely crinoidal (flat reef) [SK 1650 8193]

8

(i) Clay parting

0 to 0.25

(h) Limestone, grey to dark grey massive fine-grained; some crinoid debris

3.5 to 6

(g) Limestone, dark thin-bedded fine-grained, with shale partings; abundant large shells

3 to 3.75

(f) Limestone, grey, crinoidal

0 to3

(e) Limestone, dark massive; Saccamminopsis in middle, some large shells in lowest 2.5 ft

7

(d) Clay parting, thin

(c) Limestone, pale grey crinoidal

4.25 to 10

(b) Limestone, dark well-bedded, finely crinoidal and bioclastic; L. junceum 1 ft from base

6

(a) Limestone, dark finely crinoidal with partings of black shale and small limestone pebbles; Saccamminopsis sp. throughout

5

Bee Low Limestones

The highest bed (j), representing the "second calcirudite" appears to join the overlying "third calcirudite" to form a composite mass of flat-reef limestones which can be followed for some 200 yd eastwards from this section. Northwards the flat reef passes laterally into apron-reef. The "first calcirudite" is represented in the section by bed (c).

To the south of the quarry area an outcrop of Lower Monsal Dale Beds is present though the limits of this are uncertain. With the exception of Nether Cotes boreholes NC6 to NC8 (see (Plate 5)) there is little information on the detailed stratigraphy of this tract and the relationships are complicated by the lateral passage of the standard limestones into basin facies (see also p. 91) with the development of dark cherty limestones.

Litton Tuff
Cressbrook Dale

The outcrop of the Litton Tuff is well marked though exposures are poor and infrequent. Due east of Litton the tuff (loc. 55q) overlies the beds listed on p. 67, and is some 42 ft thick; the northernmost part of the outcrop [SK 1732 7536] shows only some 25 ft of tuff. The landslip feature of Peter's Stone is due to the slipping of the overlying beds on the Litton Tuff.

Litton

The tuff reaches its maximum development of 100 ft on the slopes north and north-east of the village, the overlying limestones giving rise to a strong feature. Exposures are present in the roadside between Peep o'Day and Litton village, one [SK 1682 7518] close below the top showing 12 ft of weathered brown tuff. A trench [SK 1676 7517] in the roadside 0.25 mile E.S.E. of Stemdale House showed greenish brown calcareous tuff with vesicular cognate lapilli and bombs up to 5 in diameter. The thickness of the tuff at Litton and the presence of the coarse ejectamenta strongly suggest proximity to the source of the deposit.

To the north-east of Litton, the Littonfields Borehole [SK 1752 7596] proved the tuff between 269.5 and 280 ft. The uppermost 8.5 ft were not recovered, but the lowest 2 ft were a pale grey fine-grained tuff. Wardlow Mires No. 1 Borehole [SK 1850 7553] (see pp. 91, 93) proved grey-blue fine-grained tuff 2 ft 6.5 in thick at 452 ft; records of boreholes and shafts north of here show the tuff to be absent.

Tideswell to Tideswell Moor

From the type locality the outcrop of the Litton. Tuff extends north-westwards and then northwards as a conspicuous slack which is traceable as far as Bushy Heath where the tuff dies out. In general exposures are lacking, though there are shows of yellow clay in places. In this area the Litton Tuff has been seen in trenches. In the main A 623 road [SK 1525 7663] to [SK 1529 7661] weathered brown igneous rock was encountered. Another section on a side-road [SK 1529 7641] to [SK 1521 7639] showed weathered tuff, very fine-grained and limonitic in places.

Upper Monsal Dale Beds
Middleton Dale

Here much of the upper part of the Upper Monsal Dale Beds is continuously exposed (see (Figure 9)). Detailed sections at three places are given below to illustrate the succession, and these and supplementary sections are shown on (Figure 10). The sequence was first described by Morris (1929, pp. 37–67), some of whose strati-graphical terms are retained. Two shell bands, here termed the Lower and Upper Shell beds, are traceable over much of the dale and form convenient datum-horizons. The bed of white calcilutite termed the "White Bed" by Morris (ibid., p. 47–8) is also a useful datum, and near the top of these beds the Orionastraea

Band has been followed over part of the section (see (Figure 10)). Towards the western end of the date the section (loc. 73) in Furness Quarry [SK 2085 7596] is as follows:

feet

Eyam Limestones (see p. 99), clay parting at base [SK 2100 7608]

(x) Limestone, grey-white massive fine-grained, with scattered fine crinoid debris and some shells

8.75

(w) Limestone, as above but cherty

5

(v) Clay parting, on slight erosion surface

0 to 0.25

(u) Limestone, pale grey-brown fine-grained; fairly abundant chert; a 15-in coral band 2 ft from base with Lonsdaleia duplicata duplicata

3.5

(t) Limestone, pale very cherry; a few productoids near base

4

(s) Limestone, pale cherty

1.5

(r) Orionastraea Band: pale cherty limestone with Diphyphyllum lateseptatum, Lithostrotion junceum, L. pauciradiale, L. portlocki, Orionastraea placentaThe collections from this and the overlying coral band were made from the access-road on the north-east side of the quarry.

2.25

(q) Limestone, pale cherty

6

(p) Lonsdaleia duplicata Band: pale, massive limestone with scattered chert; 1-ft bed with corals 30 ft from base, D. lateseptatum, Lithostrotion junceum, L. pauciradiale, L. portlocki, Lonsdaleia duplicata duplicata

51

(o) Chert, dark, rather irregularly developed

4 in to 0.75

(n) White Bed: calcilutite, pale grey, with some chert

4.5

(m) Limestone, pale grey, with rare chert

20.5

(l) Clay, thin wayboard on slight erosion surface

(k) Limestone, pale fine-grained, with a little dark chert

7.5

(j) Limestone, grey-brown massive; an impersistent line of chert nodules at 4.75 ft from top (in north-east of section)

8.5

(1) Upper Shell Bed: limestone, pale fine-grained Shelly

1 to 3

(h) Limestone, grey

11.5

(g) Clay, on slight erosion surface

0 to0.25

(f) Limestone, as above

12

(e) Clay parting

1 in to0.25

(d) Black Bed: limestone, dark; corals including Lonsdaleia floriformis

5 in to 0.75

(c) Clay

thin

(b) Limestone, pale grey massive; slight erosion surface at 9.5 ft from base

28.5

(a) Limestone, pale crinoidal, slight erosion surface 2 ft from base

6.5

The two erosion surfaces in items (a) and (b) lie near the horizon of the Lower Shell Bed and one or other may be responsible for its absence (see also p. 81). The Black Bed (d) is thin compared with the sections quoted below.

Farther down the dale, the section (loc. 74) at Shining Cliff [SK 2184 7582] (Plate 1) is as follows:

feet

Eyam Limestones (see p.98)

(u) Limestone, pale massive fine-grained oolitic, with a little fine crinoid debris [SK 2193 7592]

6

(t) Limestone, pale well-bedded cherty; finely granular and crinoidal in lowest 4 ft, passing up into buff calcilutite; fossiliferous near top, with Rotiphyllum costatum, Gigantoproductus edelburgensis, Productus productus

16

(s) Limestone, off-white fine-grained cherty

1.75

(r) Limestone, buff massive fine-grained cherty; 3-in band of pseudobreccia 15.5 ft from base; impersistent thin coral band 14 ft from base; brachiopods including P. productus hispidus

25.75

(q) Dibunophyllum aff. muirheadi Bed: limestone, grey-white fine-grained Shelly; Dibunophyllum bipartitum bipartitum, D. bipartitum konincki, Lithostrotion junceum, L. pauciradiale, Palaeosmilia regia, G. edelburgensis

1

(p) Limestone, off-white fine-grained

(o) White Bed: buff to white calcilutite, with bands and nodules of chert in top 3 ft; white-weathering

7

(n) Limestone, medium to pale grey-brown, darker at top, a little chert; lowest 12 ft with scattered shells

18

(m) Limestone, pale brown fine-grained; many silicified shells in top 3 ft; G. crassiventer, G. dentifer

11

(l) Upper Shell Bed: massive pale limestone with abundant G. crassiventer? and G. dentifer?

1.5

(k) Limestone, pale massive, brown at base; 6-in band at 3 ft from base with L. junceum, L. pauciradiale, Lonsdaleia floriformis floriformis (Lonsdaleia Bed of Morris); Lonsdaleia floriformis floriformis at 7 ft above base: Diphyphyllum lateseptatum, Lithostrotion junceum, L. pauciradiate, L. portlocki and brachiopods at 8 to 11 ft from base; gigantoproductoids at 14.5 ft from base

23.5

(j) Black Bed: limestone, dark bituminous; scattered shells; Lonsdaleia floriformis floriformis

4.75

(i) Limestone, pale grey, variegated darker in top 3 in; abundant corals in top 1 ft 2 in; D. lateseptatum and Syringopora sp.

5

(h) Not exposed

2

(g) Limestone, pale grey massive, with scattered crinoid debris

3.75

(f) Lower Shell Bed: off-white to buff fine- to very fine-grained limestone with abundant shells, some silicified; a little chert in lowest 2.5 ft; G. sp. edelburgensis group, G. sp. cf. moderatus

(e) Limestone, grey-white fine-grained; 5-in bed of fine shell debris 1 ft from base; prominent slightly irregular bedding plane 4 ft from base

5.5

(d) Limestone, grey-brown, finely crinoidal at base, less crinoidal above

7.5

(c) Limestone, buff to grey-white finely crinoidal; scattered productoids in upper half include G. edelburgensis

17.5

(b) Not exposed about

12

(a) Limestone, buff crinoidal, with some sorting into coarse and fine bands

7

This appears to be the type section for Middleton Dale described in detail by Morris (1929, pp. 45–8); Shirley and Horsfield (1945, p. 294) suggest that the succession is a condensed one. (Figure 10) shows that the local thinning of the upper part of the succession is restricted to the beds just above the White Bed and is best explained by the presence of a local non-sequence at this horizon, though this is difficult to observe in any one section (see also p. 81).

The third detailed section in Middleton Dale is that at Castle Rock (loc. 75) [SK 2247 7569]:

feet

Eyam Limestones( see p.99)

(z) Limestone, buff; shelly, including Gigantoproductus sp.

12

(y) Limestone, pale fine-grained

1

(x) Limestone, pale crinoidal and shelly, 'rubbly-weathering'; Antiquatonia cf. hindi, Krotovia spinulosa, Overtonia fimbriata, Semiplanus sp. latissimus group [juv.] near base

8

(w) Limestone, pale massive fine-grained cherty; 3-in soft-weathering band at base

6

(v) Limestone, buff well-bedded fine-grained with rare chert

9

(u) Not exposed about

6

(t) Limestone, pale massive fine-grained

3

(s) Limestone, buff finely crinoidal, rubbly in places at base

6.5

(r) Limestone, pale grey-brown fine-grained; marked bedding plane ( ?erosional) with traces of clay 3 ft from base

4.75

(q) Limestone, pale cherty (especially at base)

1

(p) Limestone, pale massive finely bioclastic, some chert about 5 ft from base; scattered corals 4 to 6.5 ft from base; L. junceum, L. martini and L. cf. portlocki

8.25

(o) Clay parting thin

(n) Limestone, pale brown fine-grained irregular-weathering [forms gash in cliff face]

6.5

Slight erosion surface

(m) Limestone, pale grey massive fine-grained, scattered shells and sporadic corals near base

12.25

(l) Upper Shell Bed: buff fine-grained to finely granular shelly limestone; G. crassiventer

4.25

(k) Limestone, pale grey-brown massive fine-grained, with a few shells; prominent bedding plane at base

6.25

(j) Limestone, buff massive fine-grained; silicified coral 1.5 ft from top

7.75

(i) Limestone, pale grey-brown massive finely crinoidal ; scattered shells

4.75

(h) Limestone, as above, with a little chert at base; Lonsdaleia floriformis fioriformis 6 in from base

4.5

(g) Black Bed: limestone, dark fine-grained, top 9 in rubbly weathering; colony of Lithostrotion portlocki 3 ft from base

5.25

(f) Clay parting, thin, on prominent bedding plane

(e) Limestone, dark fine-grained; corals including D. lateseptatum in top 1 ft

2

(d) Limestone, pale grey-brown massive; some fine crinoid debris; 1 ft with scattered shells 5 ft from base and a few shells above this

8.25

(c) Lower Shell Bed; pale limestone with abundant G. edelburgensis

6

(b) Limestone, pale fine-grained; scattered corals at base

1.75

(a) Limestone, pale grey to buff massive finely granular; 4-in shelly band with coral 6 ft from base

17

Shirley and Horsfield (ibid., p. 294) record Orionastraea cf. indivisa from "90 feet above the roadway"; this is about 45 ft above the Upper Shell Bed.

The cliff section (loc. 76) in Stoney Middleton [SK 2279 7560] 0.5 mile E.N.E. of Highfields Farm shows the highest beds in a more accessible position than at Castle Rock:

feet

inches

Eyam Limestones (see p. 98), potholed surface at base

(n) Limestone, pale granular

2

0

(m) Clay parting, on slightly eroded surface

0 to 1

(l) Calcilutite, buff to white

2

6

(k) Limestone, grey-white and buff granular bioclastic somewhat 'reef-like' in lowest 4.5 ft; coarsely crinoidal lens at 4.5 ft from base; uppermost 2.5 ft mainly fine-grained

7

0

(j) Limestone, pale massive cherty

12

6

(i) Limestone, pale cherty bioelastic, part finely crinoidal, rubbly-textured, bedding irregular

14

0

(h) Limestone, pale cherty; some corals in lowest 1 ft; L. junceum

11

0

(g) Orionastraea Band: pale limestone with some chert, L. junceum, L. portlocki, O. aff. indivisa

1

9

(f) Limestone, pale shelly, 'reef-like', thinning out in places maximum

5

8

?Slight erosion surface

(e) Limestone, pale massive cherty (especially in lower two-thirds)

10

(d) Limestone, buff fine-grained cherty; finely bioclastic in upper part with scattered corals; shell and crinoid debris

13

8

(c) White Bed: pale grey to pale buff cherty calcilutite

2

4

(b) Limestone, pale cherty, irregularly bedded and 'reef-like' with many small shells; a 9-in coral band at 3.25 ft from base with Dibunophyllum bipartitum konincki, Diphyphyllum fasciculatum, L. junceum

4

6

(a) Limestone, pale buff massive; irregular chert band at 9.75 ft from base; corals 10 to 11 ft from base; L. junceum, L. portlocki, O. placenta

16

0

The section starts about 2 ft above the Upper Shell Bed.

The most important features of the succession in Middleton Dale are summarized below and should be read in conjunction with the detailed sections already given (see also (Figure 10)):

(1) Beds below the Lower Shell Bed. These are present in the floor of the dale from the vicinity of Hanging Flat to Castle Rock. The greatest thicknesses are seen at Shining Cliff (see p. 78) and in Eyam Quarry [SK 211 756]. The latter shows some 46 ft of limestone, mainly pale massive and crinoidal, below the Lower Shell Bed. The relations of these beds to the underlying but unexposed basalt of the Middleton Dale Borehole are discussed on p. 96.

(2) The Lower Shell Bed "Lower Giganteus Bed" of Morris (1929, p. 45) is recognizable throughout the dale east of the longitude of Farnsley Farm. To the west it cannot be recognized with certainty, but it is probably thinly developed in a section west of Hanging Flat.

(3) The beds between Lower and Upper Shell beds are about 35 to 40 ft thick, and consist of pale massive limestones with a bed of dark bituminous limestone up to 5 ft at, or just below, the middle; this may be conveniently termed the 'Black Bed'. The "Lonsdaleia Bed" of Morris (ibid., pp. 42, 46) lies some 3 ft above the dark limestone but appears to be only locally developed.

(4) The Upper Shell Bed ("Hemisphaericus Bed" of Morris ibid., p. 46) is traceable around most of the dale but may be seen to fail in Eyam Quarry. In Furness Quarry also the bed was absent, but farther west it probably reappears.

(5) The beds between the Upper Shell Bed and the White Bed, 20 to 25 ft thick, are pale massive limestones showing the incoming of chert in the upper half, most of the beds above this horizon being cherty. The appearance of chert occurs at about the same horizon throughout the considerable distance covered by the dale.

(6) The White Bed, where fully developed, is up to 7 ft thick, and is so called from its white weathering, a feature which causes it to be very evident on the cliff sections. In many places this bed weathers more rapidly than those above and below and it forms a horizontal gash in the natural sections. The White Bed is absent at Castle Rock where Shirley and Horsfield (1945, p. 294) considered that it had been cut out by the overlying "Hackly Bed". The uppermost part of the bed may be seen to fail before the lower on the west side of Castle Rock, which indeed suggests the cutting out of the bed. The section at Castle Rock shows no evidence of the "conglomerate" noted by Shirley and Horsfield (ibid., p. 294) and the record may be due to the deceptive appearance of fragments of the overlying bed resting on a slightly eroded surface or on a stylolitic bedding plane. Farther east, the White Bed reappears in the cliff at Stoney Middleton.

(7) The beds above the White Bed are 75 ft thick where fully developed, though only 53 ft 7 in at Shining Cliff. They are massive cherty limestones with an irregularly weathering bed (the irregularities being due to a large number of random small joints), the "Hackly Bed" of Morris (op. cit., p. 48), at the base. The Orionastraea Band, normally some 50 ft above the base, has been traced from Furness Quarry to Eyam Dale. It has not been found at Shining Cliff though Shirley and Horsfield (1945, p. 294) record O. placenta from this horizon "at a point intermediate between this (Castle Rock) and Shining Cliff and about 20 ft above the 'White Bed' of Morris". The Lonsdaleia duplicata Band is present in Furness Quarry 27 ft below the Orionastraea Band and may be represented at Shining Cliff by the Dibunophyllum off. muirheadi Bed of Morris, though this does not appear to continue far along the section. Near the top a higher band with Lonsdaleia duplicata duplicata is present locally a few feet above the Orionastraea Band and would appear to be the lateral equivalent of the higher of the two Orionastraea bands of the Coombs Dale section (see p. 82). The thickness variation noted above appears to affect the lowest part of these beds only and is attributed to the presence of a non-sequence rather than to the condensation of the sequence suggested by Shirley and Horsfield. The non-sequence cannot, however, be directly observed in the sections. At the eastern end of Middleton Dale the bedding of this group of strata becomes rather irregular, individual beds thinning and thickening, though this does not affect the overall pattern of the group as a whole.

Cutting out of beds beneath the Eyam Limestones cannot be observed in Middleton Dale though a strongly potholed surface is present at the junction in Stoney Middleton.

Coombs Dale and Middleton Moor

In the part of Coombs Dale falling within the present district, exposure of the Upper Monsal Dale Beds is much less complete than in Middleton Dale. The best sections are at the junction of a southern tributary dale with the main dale. The highest beds are seen at a cliff (loc. 77) on the eastern side of the tributary dale [SK 2239 7429]:

feet

Eyam Limestones (see p. 98)

(f) Limestone, grey-white, fine-grained cherty

3.5

(e) Limestone, buff fine-grained; Aulophyllum fungites cumbriense, Diphyphyllum lateseptatum, D. cf. parricida, Lithostrotion junceum, O. placenta, Antiquatonia insculpta, Productus productus hispidus

3

(d) Limestone, buff fine-grained cherty; Antiquatonia hindi, A. insculpta, Avonia thomasi, Eomarginifera lobata aff. Iaqueata

22

(c) Orionastraea Band: limestone, pale grey-brown cherty; Dibunophyllum bipartiturn bipartitum, Diphyphyllum lateseptaturn, L. junceum, L. portlocki, O. placenta, Palaeosmilia murchisoni, Zaphrentites derbiensis, Alitaria panderi, Antiquatonia antiquata, A. hindi wettonensis, Echinoconchus punctatus, Spirifer (Fusella) triangularis

10

(b) Not exposed about

17

(a) Limestone, dark poorly exposed about

12

The lower coral band (c) appears to represent the main Orionastraea horizon of Middleton Dale and Bradwell Dale. Some 75 ft of little-exposed beds separate the dark limestone (a) from the lowest beds exposed in the floor of the dale (loc. 78) [SK 2222 7436]:

feet

inches

(m) Limestone, dark fine-grained

3

0

(1) Limestone, medium to pale grey-brown, massive at top, fine-grained; G. crassiventer, G. edelburgensis

8

0

(k) Limestone, dark grey fine-grained slightly bituminous and very cherty; shelly in places

5

4

(j) Limestone, pale grey-brown; some shells and broken shell debris

6

(i) Limestone, pale brown fine-grained; shelly in top 4 in; G. crassiventer, G. edelburgensis

1

9

(h) Not exposed

5

0

(g) Limestone, pale brown shelly; G. crassiventer

3

4

(f) Limestone, pale brown fine-grained cherty, with shelly bands

5

8

(e) Calcilutite, pale brown, with abundant chert

1

3

(d) Limestone, pale grey-brown cherty, with thin bands of silicified shells; G. edelburgensis

2

8

(c)?Hob's House Coral Band: limestone, medium to pale grey and grey-brown fine-grained cherty; with abundant corals, sporadic shells also in top 2 ft; Caninia juddi cambrensis, Dibunophyllum bipartitum bipartitum, D. bipartitum konincki, Diphyphyllum lateseptatum, L. junceum, L. martini, L. sp. cf. pauciradiale [with cerioid tendency]

5

10

(b) Limestone, thin-bedded fine-grained cherty; some shells near top ; G. edelburgensis

4

6

Prominent irregular bedding plane

(a) Limestone, pale brown finely crinoidal, massive except for top 2.5 ft; 9-in shell band 5 ft 8 in from base, with G. crassiventer, G. sp. cf. semiglobosus, Linoproductus sp. hemisphaericus group

15

4

The dark limestone beneath the main Orionastraea Band is developed on both sides of Coombs Dale for 0.25 mile north and to the west of the junction with the tributary dale.

Between Coombs Dale and Middleton Dale high Monsal Dale Beds (apparently all in the pale cherty limestones of the Middleton Dale sequence) occupy an undulating plateau.

This shows few sections of importance, though recent excavations at Messrs. Glebe Mines' Cavendish Mill showed the following section (loc. 79) [SK 2054 7534]; Eyam Limestones (see p. 101) on 16 ft of pale limestones, part cherty with a l.5-ft band at 8 ft from base with Diphyphyllum lateseptatum, L. junceum and L. pauciradiale. The same band, or one close to this horizon, is exposed (loc. 80) near the head of Middleton Dale [SK 1980 7616]; pale cherty limestone 5 ft, with abundant corals, including Dibunophyllum bipartitum bipartitum and D. bipartitum craigianum, in top 1.75 ft. The horizon is about 25 ft below the Eyam Limestones and the band is referred to the main Orionastraea horizon.

Cressbrook Dale

In this dale the Upper Monsal Dale Beds can be divided naturally into two groups at the horizon of the Hob's House Coral Band. The lower group consists of some 60 ft (see Littonfields Borehole, p. 84) of limestones, dark at the base and in general poorly exposed. These beds correspond to a more extensive development of dark limestones north of Litton (see p. 85). The Upper Girvanella Band at the base was recorded by Shirley and Horsfield (1945, p. 297) "on the west side of the wall at the foot of the slope" (loc. 81) [SK 1731 7537]. The thickness of the exposed part of the band is here about 1 ft, the lower beds immediately above the Litton Tuff being unexposed. During the present study the Upper Girvanella Band, 5.5 ft thick and consisting of dark limestones with Girvanella, was seen (loc. 82) close above the Litton Tuff [SK 1715 7426] 0.33 mile S.W. of Littonfields.

On the east side of Cressbrook Dale the following section (loc. 55) continues that given on p. 67 top of section at [SK 1736 7512]:

feet

(v) Hob's House Coral Band: limestone, pale grey massive; corals including Dibunophyllum bipartitum bipartitum, Diphyphyllum lateseptatum, L. pauciradiale, L. portlocki

5

(u) Limestone, grey to pale grey, darker towards base, with irregular bedding and some shaly partings; sporadic shells and rare corals; Lithostrotion junceum, Lonsdaleia floriformis laticlavia

20

(t) Not exposed (except some small exposures of rubbly grey-brown limestone in top 6 ft)

15

(s) Limestone, grey rather crinoidal in parts, rare chert lenses

12

(r) Limestone, dark to medium grey, much lenticular dark chert; sporadic shells and corals; L. floriformis floriformis

6

(q) Litton Tuff (see p. 75)

The thickness of dark limestones in this group of strata is less than in the Litton-fields Borehole and they decrease farther southwards and are difficult to recognize on the southern limit of the district west of Wardlow Hay.

The beds above the horizon of the Hob's House Coral Band are exposed in the north-eastern part of the dale (loc. 83) [SK 1736 7538]:

Eyam Limestones (see p. 102) top of section [SK 1788 7550]

(z) Limestone, pale, part fine-grained, part slightly crinoidal; irregular fracture in lowest 4 ft

15

(y) Limestone, pale with irregular fracture; 2-in soft-weathering bands at top and bottom; band of broken compound corals 0 to 6 in at top; D. lateseptatum, Lithostrotion portlocki

0.75

(x) Limestone, pale

3 ft to 5

(w) Limestone, pale rather fine-grained, with some dark chert lenses; a 3-in chert band at 1.75 ft above base

5.5

(v) Limestone, pale; irregular fracture in top 6 in and lowest 2.5 ft; a few corals in lowest 2.5 ft; L. junceum, L. pauciradiale

11

(u) Limestone, pale, with much fine crinoid and shell debris, some chert in lowest 3 ft; scattered corals and thin band of corals 3 ft from base; D. lateseptatum, L. pauciradiale, L. portlocki, Palaeosmilia regia [horizon of Orionastraea Band]

9

(t) Limestone, pale fine-grained cherty, with nodules up to l.5 ft thick; top 2 ft with much fine shell and crinoid debris

16

(s) Limestone and clay, mixed, forming a rubbly soft-weathering band

0.33

(r) Limestone, pale; lower 3 ft weather differentially giving a hollow; Lonsdaleia duplicata duplicata

6

(q) Limestone, pale cherty, with scattered shells; bands of shells in lowest 8 ft; an impersistent band up to 9 in thick with Lithostrotion portlocki, Nemistium edmondsi, P. regia and other corals at 20 ft from base [horizon of Lonsdaleia duplicata Band]

27

(p) Limestone, pale fine-grained

1.75

(o) Limestone, pale, with some chert and a few shells; common silicified corals; Lithostrotion portlocki, Lonsdaleia floriformis flonformis

1.5

(n) Limestone, pale; scattered corals

10

(m) Limestone, pale mediumto coarse-grained, partially silicified and dark weathering; abundant small shells, some rolled; L. floriformis floriformis

2 ft to 2.5

(l) Black Bed; limestone, medium to dark grey; a few shells, some rolled; corals frequent in top 5 ft; Lithostrotion pauciradiale, L. portlocki, Lonsdaleia floriformis floriformis.

16

(k) Beds mainly unexposed (a few small exposures of pale limestone)

10

(j) Limestone, grey, finely granular, crinoidal

3

(i) Limestone, pale grey, finely granular, with silicified shells

1.5

(h) Limestone, pale

1

(g) Limestone, brown, soft-weathering

0.75

(f) Limestone, pale, very finely bioclastic; Lithostrotion portlocki and a few shells including 'Brachythyris' planicostata

8

(e) Limestone, pale, with some shell and crinoid debris; L. martini, Nemistium edmondsi; some bands of larger rolled shells in lowest 15 ft; top 5 ft oolitic in places

26

(d) Limestone, grey-brown, soft weathering; some shells and crinoid debris

2

(c) Not exposed

1

(b) Limestone, grey; broken shell debris and coral fragments

1

(a) Hob's House Coral Band: limestone, grey to dark grey, with a little chert, some argillaceous lenses; Caninia benburbensis, Dibunophyllum bipartitum bipartitum, D. bipartitum konincki, Diphyphyllum lateseptatum, L. martini, L. pauciradiale, P. murchisoni, 'B.' planicostata

9.5

The Hob's House Coral Band is underlain by 11 ft of pale massive limestone and then by 40 ft of dark limestones, cherty in part and containing the Upper Girvanella Band of locality 81 at their base.

Shirley and Horsfield (1945, p. 297) considered that a "bed 4 feet thick, with weathering along irregular small joints" at "about 14 feet" below the Eyam Limestones represented the 'Hackly Bed' and D. aff. muirheadi Bed of Middleton Dale; this correlation is rejected here (see (Plate 7)).

On the eastern side of Cressbrook Dale a crag (loc. 84) [SK 1737 7494] yielded a fish-tooth, Psephodus?, from about 5 ft below the Hob's House Coral Band.

Litton and Hucklow Moor

In this area the Upper Monsal Dale Beds occupy a broad tract with few large exposures. The subdivision into a lower group of dark limestones and a higher group of pale limestones made in Cressbrook Dale (see p. 83) still holds, and the outcrops of these subdivisions are considered separately below. Nearly all of the Upper Monsal Dale Beds was passed though in the Littonfields Borehole and all of the group in two percussive boreholesInformation from examination of cutting samples by Professor F. W. Shotton. also made by the Derwent Valley Water Board, near Great Hucklow. The record of Littonfields Borehole (loc. 85) [SK 1751 7595] may be summarized:

Thickness

Depth

feet

inches

feet

inches

No core

11

4

11

4

Limestone, pale grey cherty, with corals; (c) L. junceum

1

3

12

7

Limestone, pale grey granular; some crinoid debris to 19 ft; (b) L. portlocki at 18 ft 3 in

16

3

28

10

Limestone, pale cherty; (a) A. insculpta? and 'B.' planicostata at 31 ft

12

2

41

0

Limestone, pale fine-fine-grained, some patchy replacement by chert

5

0

46

0

Limestone, pale cherty

57

0

103

0

Limestone, pale

8

9

111

9

Calcilutite, dark (Black Bed)

1

10

113

7

Limestone, pale (little core recovered)

76

5

190

0

Limestone, dark (little core recovered); horizon of Upper Girvanella Band at base

59

0

249

0

Lower Monsal Dale Beds (see p. 69)

The section compares closely with that of the Wardlow Mires No. 1 Borehole. The lowest item is the lower, dark subdivision. As the dark bed at 113 ft 7 in is correlated with the Black Bed of Middleton Dale, the contention of Shirley and Horsfield (1945, p. 297) that the uppermost 40 ft of the Shining Cliff succession are missing in Cressbrook Dale cannot be accepted.

At outcrop the lower group of dark limestones, about 60 ft thick, is traceable over the whole of the tract. Exposures are mainly of the lowest beds in the feature of Litton Edge above the Litton Tuff. The lithology varies from grey well-bedded limestones [SK 1659 7538] to dark crinoidal and shelly limestones [SK 1605 7583] and dark cherty limestones [SK 1590 7644]. Exposures of these beds can be seen in open workings along Tideslow Rake [SK 1520 7798] to [SK 1564 7792] showing dark thin-bedded cherty limestones with some crinoidal and shelly bands. Farther north a section (loc. 86) [SK 1512 7940] on the north side of Shuttle Rake shows beds near the top of the dark limestone group:

feet

(c) Limestone, dark thin-bedded cherty

12

(b) Limestone, grey shelly, with some chert; some crinoid debris; shelly fauna includes E. lobata aff. laqueata, G. crassiventer, G. edelburgensis, P. productus hispidus

3.5

(a) Limestone, medium to dark grey poorly bedded fine-grained cherty

9.5

The upper pale beds are cherty at the top and mainly non-cherty below. For the most part, good sections are rare in this area, the best being near the top of the Monsal Dale Beds in the small dale extending north-westwards from the site of the Littonfields Borehole. A section here [SK 1717 7639] is as follows:

feet

Limestone, grey well-bedded cherty rubbly-weathering

3

Limestone, grey massive, fine-grained, abundant chert; some wedge-bedding

18

Limestone, grey massive

4

The lower part of the pale beds is less well exposed. The lithology varies from grey limestone with rolled shell debris [SK 1625 7750] to grey well-bedded limestone [SK 1677 7632]. Farther north, old open workings on High Rake show a number of sections, mainly on the northern (downthrow) side exposing grey cherty limestones in the upper part of the pale beds [SK 1673 7785]; [SK 1632 7778]. To the north of Tideslow Rake [SK 1573 7825] a section shows some of the lower part of the pale beds: grey granular limestone with bands of shells, some rolled, 11 ft.

Beds close below the Eyam Limestones are seen in a section (loc. 87) in a dry valley south-east of Little Hucklow [SK 16507813]:

feet

(l) Limestone, dark, some shells; a little chert in lowest 1 ft

8

(k) Limestone, grey, weathering nodular and soft

1.5

(j) Clay, grey, on prominent bedding plane

thin

(i) Limestone, grey, with a little chert; nodular weathering at base; poor clisiophylloids and L. junceum in top 2 ft; Caninia juddi, D. bipartitum [juv], L. junceum at base

10

(h) Clay parting, impersistent, thin

(g) Limestone, grey; a 6-in bed in middle, with thin clay partings above and below; weathers soft and nodular

12.5

(f) Not exposed

1

(e) Limestone, grey

3

(d) Not exposed

1

(c) Chert, pale

1

(b) Limestone, grey, fine-grained

6

(a) Limestone, grey fine-grained cherty, with some crinoid debris

9

The presence of dark limestones, high in the Monsal Dale Beds, should be noted here; their incoming recalls a similar development at the north end of Bradwell Dale (see p. 91). The coral band is the Orionastraea Band (Shirley and Horsfield 1945, plate xviii).

To the north of Shuttle Rake the upper pale limestones bear some chert in their lower part, for example near Berrystall Lodge [SK 1508 7989]. Higher beds are well seen in the upper part of Intake Dale [SK 1614 7949] as pale cherty limestones. A section (loc. 88) in a small dale joining Intake Dale [SK 1626 7986] shows the Orionastraea Band:

feet

(i) Orionastraea Band: limestone, pale, in three thin beds; L. portlocki, O. placenta and Pugilis pugilis

2

(h) Limestone, pale massive

2.75

(g) Not exposed about

7

(f) Calcilutite, brown-white, with chert up to 11 in at top

6

(e) Not exposed

3

(d) Limestone, pale irregularly jointed ('hackly')

4.75

(c) Limestone, pale massive fine-grained

3

(b) Lonsdaleia duplicata Band: limestone, with D. bipartitum bipartitum, L. duplicata duplicata, L. floriformis floriformis

1

(a) Limestone, pale massive fine-grained

2

The section is important as being the locality where the relationships of the Orionastraea and L. duplicata bands can be best established (see also Shirley and Horsfield 1940, p. 277). The occurrence here of L. foriformis floriformis in the L. duplicata Band is exceptional (see p. 138).

On the southern side of Intake Dale the relation of the Orionastraea Band to the Eyam Limestones is shown in the following section [SK 1635 7966]:

feet

Eyam Limestones (knoll-reef, see p. 103)

Limestone, pale grey massive fine-grained

8

Limestone, near-white fine-grained, with some chert in lower part

10

Limestone, pale brown crinoidal

2

Limestone, pale massive, finely crinoidal in places

16

Orionastraea Band: limestone, sorted, fine and coarser Shelly and crinoidal, with scattered corals

6

Limestone, pale cherty finely crinoidal, with some shells

4.5

Limestone, fine-grained cherty

11

The Orionastraea Band has evidently been subjected to considerable winnowing by current action here.

To the north of Intake Dale the Orionastraea Band has been traced to Earl Rake where an exposure (loc. 89) [SK 1619 8007] yielded Lithostrotion portlocki (a common associate of Orionastraea). Farther north a series of exposures of high Monsal Dale Beds is provided by Hartle Drake and Jenning's Dale; these show pale limestones, cherty in places and with some crinoidal bands. An exposure (loc. 90) [SK 1616 8046] at the western end of Hartle Dale is as follows:

feet

(e) Limestone, pale massive, some chert ,

1

(d) Limestone, as above, with corals, disappearing laterally; L. junceum, L. pauciradiale

1

(c) Limestone, pale massive, with a little chert; some shells at base and at 10.5 to 14 ft above base

15

(b) Limestone, fine-grained, pale grey, with silicified productoids

1.5

(a) Limestone, pale grey massive fine-fine-grained, with a little chert

4.75

The coral band was considered by Shirley and Horsfield (1940 plate xviii), to be the Orionastraea Band but it is certainly at a lower horizon and may represent the Lonsdaleia duplicata Band.

Bradwell Moor

Over much of this area exposure is poor. On the western side the presence of some dark limestones at the base of the subdivision is indicated by scattered exposures. These beds, with the Upper Girvanella Band, are well seen on the northern side of Dirtlow Rake (loc. 91) where a section [SK 1449 8155] in old open workings south-east of Hurdlow Barn shows the following:

feet

inches

(f) Limestone, dark to grey slightly bituminous

3

0

(e) Limestone, grey crystalline; Antiquatonia hindi, A. sulcata, Eomarginifera lobata aff. laqueata, E. tissingtonensis cambriensis, G. edelburgensis, G. sp. aff. moderatus

6

6

(d) Clay parting

up to 2

(c) Limestone, grey finely crinoidal, abundant 'Girvanella'nodules in lowest 1 ft

5

0

(b) Limestone, grey fine-grained; abundant 'Girvanella'nodules

1

2

(a) Limestone, pale grey

2

9

The Upper Girvanella Band, 2 ft thick, is also exposed (loc. 92) [SK 1484 8186] at a point a little north of Dirtlow Rake. In the area north of Dirtlow Rake, the band is succeeded by some 20 ft of dark limestones and these by a small knoll-reef [SK 145 817].

The beds between the lowest dark limestones and the L. duplicata Band are little exposed, and knowledge of them is largely from boreholes. A detailed log of a typical hole (No. BM 27) and a partial log of another (No. BM 28) have already been published (Eden and others 1964, pp. 107–10) and these and other typical records are shown graphically in (Plate 8). An exposure (loc. 93) [SK 1424 8045] about 100 ft above the base in the central part of Bradwell Moor showed 19 ft of pale limestone with Shelly and crinoidal bands and large chert masses in the lowest 4 ft; the fauna included G. crassiventer, G. dentifer and G. giganteus cf. crassus.

Beds from the L. duplicata Band upwards form an oval outcrop in the central area of Bradwell Moor. The L. duplicata Band has been proved in Borehole BM 32B [SK 1475 8121] (see Appendix 1, p. 362) and lies some 190 ft above the Upper Girvanella Band. It is exposed (loc. 94) [SK 1471 8114] in an old quarry:

feet

(b) Limestone, pale fine-grained

2.75

(a) Limestone, pale; Diphyphyllum furcatum, Lithostrotion portlocki, Lonsdaleia duplicata duplicata, Nemistium edmondsi, brachiopods and rare trilobites

2.5

On the eastern side of the outcrop the L. duplicata Band is again exposed (loc. 95) [SK 1525 8123] and Eden and others (1964, pp. 99, 106) list L. duplicata duplicata and brachiopods from this locality. Near this exposure a knoll-reef is developed just above the L. duplicata Band.

Farther east Shirley and Horsfield (1940, p. 281) noted the presence of the L. duplicata Band near Bird Mine. The following section (loc. 96) [SK 1565 8118] was measured during the present work:

feet

(c) Limestone, pale coarsely crinoidal

1.25

(b) L. duplicata Band: limestone, crinoidal and cherty; D. lateseptatum, L. duplicata [rare], P. regia, A. insculpta, Productus productus hispidus, Pugilis pugilis

2.75

(a) Limestone, pale fine-grained cherty

5

To the north of Bradwellmoor Barn an area nearly 0.25 mile wide and extending for 0.5 mile parallel to Dirtlow Rake on its south side is strewn with large blocks of silicified limestone. The largest of these [SK 1543 8199] reaches a thickness of 15 ft and shows traces of purple fluorite. The disposition of the blocks makes it clear that they result from the erosion of a horizon which has suffered preferential silicification adjacent to Dirtlow Rake. The horizon was probably not far from that of the L. duplicata Band (see also p. 313).

Earle's Quarry

In the quarry the lowermost 100 ft or so of the Upper Monsal Dale Beds with the Upper Girvanella Band are present. These beds are predominantly dark limestones (Eden and others 1964, pp. 85–6) with six well-defined but impersistent paler calcirudite bands up to 15 ft in thickness. The calcirudite bands in places pass laterally into knoll-reefs in the vicinity of which they are at their coarsest; towards the reef-belt these beds show an increase in the rounding of their constituents and in extreme cases constitute rolled-shell limestones. The dark limestones also show some lateral variation, becoming more crinoidal towards the reef-belt.

The section [SK 1592 8206] on the Upper Bench (1962) of the quarry (loc. 97) on the northern side of the large knoll-reef is described below (see also Eden and others 1964, pp. 99–103, 106):

feet

(j) Limestone, dark cherty (thinning and passing over top of knoll-reef)

25

(i) Limestone, dark cherty (passing into top part of knoll-reef)

10

(h) Limestone, fine-grained pale cherty, with coarsely crinoidal bands; Palaeosmilia murchisoni, abundant brachiopods including G. cf. dentifer, Productus productus hispidus (passing first into grey to pale grey non-cherty limestone before merging with the knoll-reef)

8

(g) Limestone, pale rather crinoidal; large chert nodules at base; passing southwards first into thin-bedded dark limestones and then into knoll

10

(f) Limestone, medium to dark grey crinoidal, with partings of dark shale (position of base of large knoll)

1

(e) Limestone, medium to dark grey, lowest 6 ft cherty in northern part of section; some shells in lowest 6 ft

11

(d) Limestone, dark to medium grey thin-bedded crinoidal; bands of dark chert nodules in top 5 ft; occasional clay partings

11

(c) Clay parting about

0.25

(b) Limestone, grey

4.5

(a) Upper Girvanella Band: limestone, dark to medium grey, with some dark chert, sporadic shells; lowest 2.5 ft rather crinoidal with dark shale partings and some breccia fragments near the reef margin; abundant Girvanella staminea

10

The large knoll-reef [SK 1576 8180] referred to (Eden and others 1964, pp. 87–9) as the "main knoll" is the equivalent of beds (f) to (l) inclusive, reaches a thickness of 55 ft and appears to result from the combination of two horizons of minor knolls, the lower some 30 ft above the Upper Girvanella Band, the higher some 50 ft above it. It is composed of unbedded vughy calcilutite with intercalations of dark calcarenite at the edges. Some breccia and a little crinoid debris are present. The fauna of the knoll (loc. 98) includes the goniatite Bollandites sp. in addition to a rich brachiopod fauna; Palaeosmilia murchisoni with P. regia is abundant in a 6-in band near the top. Another knoll [SK 1582 8171] of large dimensions is present 100 yd S.E. of the "main knoll" and lies at the same horizon.

At the south-eastern end of the quarry [SK 163 818] a marked unconformity develops at the base of the Upper Girvanella Band as the tuff mound (see p. 74) is approached.

Smalldale and Bradwell

To the south-east of Earle's Quarry the relations of the lower part of the Upper Monsal Dale Beds are complicated by the lateral passage of pale limestones into dark thin-bedded limestones near the margin of the basinal area (see also p. 91). This phenomenon has already been noted in the Lower Monsal Dale Beds. The two subdivisions are indistinct as a result.

The greater part of the beds described in the quarry passes rapidly southwards into coarsely crinoidal limestones. A borehole, NC1 [SK 1627 8152] proved these limestones to a depth of 87 ft, underlain by dark crinoidal limestones to 99 ft and grey and dark grey bioclastic limestones with 'Girvanella' (the Upper Girvanella Band) to 106 ft. The pale crinoidal limestones, although not completely reef-like, show some affinities with a large flat reef in their development. A typical exposure [SK 1648 8132] at Smalldale Head shows 12 ft of pale coarsely crinoidal limestone on 5 ft of pale cherty limestone. The crinoidal limestones extend southwards to, and a little beyond, Moss Rake, though displaced by the latter. At Outlands Head a quarry [SK 1661 8080] shows 30 ft of pale shelly and often crinoidal limestone. South of Outlands Head the top of the crinoidal beds must lie not far below the Orionastraea Band.

Towards the margin of the limestone outcrop, pale cherty limestones down to about 100 ft below the Orionastraea Band persist locally on the south side of Bradwell. To the south-east, these limestones can be observed to pass into dark limestones and the junction with dark limestones in Bradwell village may also be diachronous.

Bradwell Dale

The main features of the stratigraphy of this dale are summarized in (Figure 11). Two detailed sections are quoted below and other sections are shown graphically in the figure. Variations in the succession are discussed below.

The most complete section measured (loc. 99) is near the southern end of the dale"Morton's quarry" of Shirley and Horsfield.. [SK 1714 8039]:

feet

Eyam Limestones (see p. 104)

(f) Limestone, pale fine-grained, very finely crinoidal; some wedge-bedding near top; colony of Lithostrotion decipiens in position of growth at 9 ft from base about

12

(e) Limestone, pale irregularly bedded cherty, with a little crinoid debris; 9-in band 1.25 ft from top with Lithostrotion junceum, Lonsdaleia duplicata and productoids

22

(d) Limestone, pale shelly crinoidal, in three 8- to 10-in beds; Antiquatonia cf. antiquata, A. insculpta, Avonia thomasi, A. youngiana, E. lobata laqueata, Semiplanus sp. latissimus group

2.25

(c) Orionastraea Band: limestone, pale cherty; Lithostrotion decipiens, L. junceum, O. placenta, Antiquatonia hindi, A. insculpta, 'B.' planicostata, Krotovia spinulosa

3.75

(b) Limestone, pale massive fine-grained cherty, in 3- to 4-ft beds; scattered crinoid debris, finely crinoidal in lowest 2 ft

24

(a) Limestone, pale grey-brown crinoidal (some columnals up to 1 in diameter), with bands of pale chert, well-bedded; scattered productoids

12

At the northern end of Bradwell Dale the following section (loc. 100) [SK 1741 8077] was measured:The lettering of beds on this implies no correlation with the preceding section.

feet

Eyam Limestones (see p. 104)

(k) Limestone, pale thin-bedded; A. insculpta

1

(j) Orionastraea Band: limestone, pale thin-bedded, with a little chert; Clisiophyllum keyserlingi, Dibunophyllum bipartitum bipartitum, Diphyphyllum lateseptatum, L. decipiens, L. junceum, L. portlocki, Palaeosmilia sp.

3.75

(i) Limestone, pale cherty, with scattered crinoid stems and shells

4.75

(h) Limestone, grey-brown finely crinoidal, with chert

4.25

(g) Limestone, pale irregularly-bedded cherty, with some coarse crinoid debris; productoids

5.25

(f) Limestone, pale massive fine-grained, with some chert; limestone pebbles up to 0.75 in diameter; G. edelburgensis, G. sp. cf. bisati

5.75

(e) Limestone, pale grey evenly bedded cherty (especially in lowest 6 ft), finely crinoidal in places

13.75

(d) Limestone, dark to medium grey thin-bedded cherty, with fine wavy banding

8.75

(c) Limestone, pale massive, with coarse crinoid debris, cherty in lowest 2.5 ft.

6

(b) Limestone, medium to pale grey massive cherty, crinoidal; chert in lenses up to 2 ft thick; gigantoproductoids at top and base and G. crassiventer at 4 ft from top

17.5

(a) Limestone, medium to dark grey thin-bedded and irregularly banded; much dark chert; very dark at base

5

The general features of the succession in Bradwell Dale may be summarized as follows:

1. Beds below the Orionastraea Band. These show two non-sequences. The lower is present locally in the northern half of the dale in the position of bed (f) of loc. 100 as a pebbly horizon some 20 ft below the Orionastraea Band; it can be seen as an angular break some 100 yd S. of loc. 100. A higher non-sequence, about 7 ft below the Orionastraea Band, is well seen (see (Plate 9A)) at the southern end of the dale [SK 1722 8046]; beneath lie some 10 ft of massive crinoidal and shelly limestone, bed (a) of loc. 99. The lower beds are folded into an east–west anticline, the upper 8 ft or so being cut out by the non-sequence.The direction of folding and lithological similarity with the lowest beds of loc. 100 are taken to indicate that the structure is anticlinal rather than of knoll form. At this locality the uppermost 3 ft of beds below the Orionastraea Band also bear corals.

To the north of loc. 100 the uppermost part of these beds, down to a horizon a few feet below the Orionastraea Band, is cut out progressively by the unconformity at the base of the Eyam Limestones. The underlying beds pass northwards into thin-bedded dark cherty limestones, which persist at some horizons, e.g. beds (a) and (d) of loc. 100, southwards for some distance into beds of normal shelf facies (see (Figure 11)).

By comparison with the section in Intake Dale a sufficient thickness of strata is exposed for the Lonsdaleia duplicata Band to be present in Bradwell Dale. However, no corals have been seen at this horizon.

2. Orionastraea Band and overlying strata. At the southern end of Bradwell Dale exposures do not allow the joining of the outcrops of the marker-band on the two sides of the dale; otherwise it can be traced around the sides of the dale until it is cut out by the unconformity at the base of the Eyam Limestones. The beds above the Orionastraea Band consist of pale limestones, some cherty, with rather 'reef-like' shelly and crinoidal beds in places.

Concealed Monsal Dale Beds
Wardlow Mires, Great Hucklow and Eyam

The Wardlow Mires No. 1 Borehole (loc. 101) [SK 1850 7553] proved Monsal Dale Beds, overlain by Eyam Limestones, between 113.5 ft and the base of the borehole at 632 ft 2 in. The correlation is illustrated in (Figure 12); the sequence is summarized below:

Thickness

Depth

feet

inches

feet

inches

Eyam Limestones (see p. 102)

113

6

113

6

Limestone, pale, cherty in places; Orionastraea

Band 1 ft 7 in at 150 ft, with Dibunophyllum sp., Diphyphyllum sp. and Lithostrotion portlocki

57

2

170

8

Calcilutite, cherty

2

7

173

3

Limestone, pale, with rare chert; L. duplicata Band at 193 ft

68

5

241

8

Limestone, dark fine-grained (Black Bed of Middleton Dale section)

4

4

246

0

Limestone, pale; Lonsdaleia floriformis at 249 ft 4 in; Lithostrotion portlocki at 252 ft 2 in

47

9.5

293

9.5

Calcilutite, buff

2

0.5

295

10

Limestone, pale, with some crinoidal bands; partly oolitic from 356 ft 7 in to 361 ft 4 in; bioclastic and shelly at base

68

10

364

8

Limestone, dark, with 'Girvanella' (Upper Girvanella Band)

5

4

370

0

Limestone, pale crinoidal, shelly in places, partly oolitic near top

12

10

382

10

Limestone, pale predominantly oolitic, some chert in places, crinoidal at base

44

9

427

7

Limestone, partly crinoidal, with some chert; shelly in lower part

7

1

434

8

Limestone, dark cherty; Lingula in places; crinoidal below 446 ft 6 in; lowest 0.5 in tuffaceous

14

9.5

449

5.5

Tuff, grey fine-grained (Litton Tuff)

2

6.5

452

0

Limestone, dark

6

1.5

458

1.5

Limestone, pale bioclastic and finely oolitic

9

5.5

467

7

Limestone, dark

5

5

473

0

Mudstone, dark calcareous

2

5

475

5

Limestone, pale buff; crinoidal below 486 ft

32

5

507

10

Lava, mostly amygdaloidal but in places compact and non-vesicular (Cressbrook Dale Lava)

105

5.5

613

3.5

Tuff

1

2.5

614

6

Limestone, grey to dark grey

7

6

622

0

Mudstone, dark calcareous

3

622

3

Limestone, grey to dark grey

9

623

0

Limestone, grey crinoidal in part

3

6

626

6

Limestone, dark bituminous

2

6.5

629

0.5

Mudstone, blue-grey

7

629

7.5

Limestone, grey-brown fine-grained

2

6.5

632

2

The presence of oolites in abundance between the Upper Girvanella Band and the Litton Tuff is abnormal and has been discussed on p. 28. The absence of the greater part of the dark beds above the Upper Girvanella Band is remarkable in view of their persistence at outcrop. The recognition of the Black Bed (see p. 81) of the Middleton Dale section provides checks on the correlation of the higher coral bands. The correlation of coral occurrences indicates a section closely comparable to that in Furness Quarry (see p. 75) and disproves the contention of Shirley and Horsfield (1945, p. 297) that some 40 ft of the top beds of D2 have been cut out in the nearby Cressbrook Dale section by the unconformity at the base of the Eyam Limestones (see (Plate 7)). Wardlow Mires No. 2 Borehole (loc. 102) [SK 1825 7586] (see Appendix 1, pp. 378–82) proved the base of the Eyam Limestones at 107 ft 9 in and pale D2 limestones from thence to the bottom of the hole at 133 ft 6 in.

The colony of L. portlocki at 129 ft 3 in represents the coral band lying just above the Orionastraea Band in the Wardlow Mires No. 1 Borehole.

Hucklow Edge No. 2 Borehole (loc. 103) [SK 2025 7760] north-east of Shepherd's Flat proved the following abridged section of the Monsal Dale Beds beneath the Eyam Limestones:

Thickness

Depth

feet

inches

feet

inches

Eyam Limestones (see p. 101); base at

344

6

Limestone, pale fine-fine-grained; with a little chert below 362 ft 11 in

26

11

371

5

Calcilutite, buff cherty

7

10

379

3

Limestone, pale, with a little chert; D. bipartitum bipartitum, Diphyphyllum furcatum and L. portlocki from 386 ft 3 in to 389 ft 1 in (Orionastraea Band)

17

10

397

1

Calcilutite, pale grey-white cherty

9

4

406

5

Limestone, pale, with finely crinoidal bands

64

9

471

2

Limestone, buff shelly, with silicified productoids (Lower Shell Bed of Middleton Dale)

8

3

479

5

Limestone, pale, with some finely crinoidal bands

23

7

503

0

Limestone, pale crinoidal; Upper Girvanella Band in lowest 11 in

1

11

504

11

Limestone, buff, somewhat crinoidal and shelly

6

6

511

5

Limestone, buff crinoidal bioclastic, shelly in lowest 1 ft 6 in

21

7

533

0

Limestone, grey-brown to buff

8

10

541

10

No core (recorded by driller as 'limestone')

3

8

545

6

Tuff, pale grey fine-grained, pyritous in part

4

8

550

2

Lava, mostly dark green amygdaloidal, non-vesicular in places, some purple mottling (Cressbrook Dale Lava)

60

6

610

8

The Cressbrook Dale Lava lies considerably nearer the base of the Eyam Limestones than in the Wardlow Mires No. 1 Borehole (see (Figure 12)) and the Upper Girvanella Band is less strongly developed. This latter is probably due to an adverse environment as the band is not normally developed in pale limestones. Many of the higher beds are readily correlated with the Middleton Dale section as indicated above. The Black Bed has, however, disappeared and the Upper Shell Bed has not been recognized. As in the case of the Middleton Dale sections chert is restricted in occurrence to the uppermost D2 strata.

The Derwent Valley Water Board No. 7 (Great Hucklow) Borehole [SK 1777 7762] at Great Hucklow, proved the following abridged successionPercussive, information from examination of cuttings by Professor F. W. Shotton.:

Thickness

Depth

feet

feet

Eyam Limestones (see p. 102)

146

Limestone, mainly pale grey cherty; darker coloured 262 to 269 ft

123

269

Limestone, pale to medium grey; some chert in lowest 30 ft

61

330

Limestone, dark cherty

10

340

Limestone, white to grey, cherty

22

362

Limestone, pale to dark grey cherty

18

380

'Shale', ashy

1

381

Limestone, pale to dark grey

12

393

Ash, grey pyritous

6

399

Basalt, hematite-stained amygdaloidal (Cressbrook Dale Lava)

6.5

405.5

The Broad Low Borehole [SK 1753 7821] north of Great Hucklow proved 257 ft of limestones below the Eyam Limestones without reaching igneous rock: pale cherty limestones 133 to 295 ft, pale to dark grey non-cherty limestones to 310 ft, medium to pale grey limestones with a little chert to 335 ft, grey to dark grey cherty limestones to bottom of hole at 390 ft. The beds from 295 to 335 ft represent the middle non-cherty subdivision and the beds below 335 ft most of the lower, dark part of the Upper Monsal Dale Beds. The Little Hucklow Borehole [SK 1684 7863] proved Monsal Dale Beds from the base of the Eyam Limestones at 34 ft to the bottom of the hole at 270 ft.

In addition to the borehole records given above, igneous rocks, all probably the Cressbrook Dale Lava, have been proved in mining at three places in this area:

1. Milldam Mine [SK 1766 7796], Great Hucklow (Pumping Engine Shaft); shale to 30 ft, limestone to 420 ft on "toadstone" (Green and others 1887, p. 136). The toadstone was stated to be amygdaloidal and so was certainly a lava. Of the overlying limestones, a comparison with the Great Hucklow Borehole section suggests that the lower 300 ft should be referred to the Monsal Dale Beds and the remainder to the Eyam Limestones.

2. Dusty Pit Mine [SK 2075 7707], Eyam, proved shale to 12 ft, limestone to 372 ft and amygdaloidal "toadstone" to 375 ft (ibid., p. 138).

3. Watergrove Sough entered 'toadstone' below the top end of Middleton Dale [SK 197 762], some 220 ft below the base of the Eyam Limestones. The latter figure indicates a rapid thinning of the D2 beds above the lava when compared with the Wardlow Mires No. 1 borehole section.

Glebe Mine

The Glebe Shaft [SK 2192 7640], Eyam, commencing at the limestone-shale junction, continued in limestone to a depth of 283 ft. The estimated thickness of the Eyam Limestones in the vicinity is about 125 ft and from this it can be inferred that the bottom of the shaft is at a horizon a little below that of the Lower Shell Bed. In the main (280-ft level) crosscut linking Glebe and Ladywash shafts, the Lower Shell Bed ("Lower Giganteus Bed") was considered to be present by Shirley (in Dunham 1952, p. 86) as a band 8-ft thick in that part of the main crosscut which follows Ashton's Pipe. The main concentration of shells is in a 2-ft band within the thicker and more sparsely shelly bed. Between the junction with Ashton's Pipe and Glebe Shaft the crosscut follows the bedding. A more detailed section by the junction with Ashton's Pipe [SK 2181 7667] is as follows:

feet

inches

Limestone, dark rubbly, with a prominent bedding-plane

10

Limestone, as below, scattered shells

3

9

Limestone, grey to buff, finely granular; shelly, especially in top 1 ft; cerioid Lithostrotion at top

2

0

The dark limestones at the top of this section are correlated with the Black Bed.

The following succession was proved below the Lower Shell Bed in a vertical borehole [SK 2181 7663] "820 ft north of the shaft" (Dunham 1952, p. 86)10n the crosscut and N.23°W. of the shaft. :

feet

Limestone

102

Toadstone

250

Limestone

33

Hard toadstone

5

Limestone

31.5

The top of the toadstone appears to be some 50 ft higher stratigraphically than in the Hucklow Edge No. 2 Borehole.

Successively higher D2 strata are present in the crosscut as it is followed northeastwards from Ashton's Pipe. These beds are described by Dunham (ibid., p. 86) as "calcite mudstones and medium-grained limestones, cherty at the top". A recent examination shows that calcilutites are restricted to an 8-ft cherty bed [SK 2194 7696] some 530 ft south of Old Edge Vein. The calcilutite is overlain by the Eyam Limestones, at the base of which a 2-in to 6-in shale parting is present. A thin clay way-board is also present beneath the calcilutite. The bed is here equated with the White Bed of Middleton Dale and the correlation is strengthened by the disposition of chert which is present above the White Bed but absent after a few feet below the bed (cf. Middleton Dale section p. 77).

From the last locality Eyam Limestones are present in the crosscut until a point 120 yd north of Old Edge Vein [SK 2203 7721] is reached (see also p. 99). To the north of the latter tract D2 beds reappear and the crosscut continues in these to the vicinity of Ladywash Shaft. The Orionastraea Band was found by Shirley (in Dunham 1952, p. 86) at the point (loc. 104) [SK 2182 7743] where the branch to Ladywash Shaft leaves the main crosscut. The band, 2 ft 6 in thick and in pale cherty limestone, yielded the following fauna: Diphyphyllum gracile, L. junceum, L. portlocki and 0. placenta.

A borehole [SK 2184 7756] near Ladywash Shaft (Schnellman and Willson 1947, p. 5) put down in 1939 at 455 ft O.D. from the 280-ft crosscut level proved:

Thickness

Depth

feet

feet

Medium-coloured limestone, cherty in upper part, fossi liferous in lower

108

108

Brecciated limestone

4

112

Lava

208

320

Irregular beds of pyritic tuff and wayboards, alternating with beds of crinoidal limestone

35

355

Medium-coloured bedded crinoidal limestone

99

454

Black limestone, very fine-grained, some chert

40

494

Light brown to light grey crystalline limestone

72

566

The dark limestones from 454 to 494 ft are equated here with the dark beds at the base of D2 and the underlying pale limestones are referred to D1.

Middleton Dale

The presence of an unexposed vesicular basalt was noted by Morris (1929, pp. 42, 44) at Hanging Flat at a horizon some 100 ft below the "Lower Giganteus Bed" (Lower Shell Bed). More recently the basalt has been proved in a borehole by the Derwent Valley Water Board at this locality [SK 2052 7600]10n the crosscut and N.23°W. of the shaft. :

Thickness

Depth

feet

feet

'Clay with stones'

Limestones, light grey; cherty in lowest 5 ft

39.5

48.5

Limestone, grey and brown crinoidal

15

63.5

Limestone, dark bituminous some shale in lower part

25

88.5

Tuff, grey calcareous and pyritous

5

93.5

Basalt, amygdaloidal except between 223 and 234 ft and below 249 ft

164

257.5

Eyam Group (P2)

Eyam Limestones
Calver and Coombs Dale

Between Calver and Calver Peak the Eyam Limestones occupy a broad sloping tract approximating to a dip-slope. They are dark limestones with extensive but apparently disconnected masses of flat-reef limestones at Calver Peak and in Calver Peak Quarries (see below). At Calver Peak, the flat reef is capped by a smaller mass of reef-limestone showing knoll form; this is frequently shelly and also shows an irregular patchy silicification, developed over large areas of the rock.

The Eyam Limestones were formerly much quarried at Calver Peak Limekiln. A section (loc. 105) of the higher beds [SK 2358 7466] is:

feet

(d) Limestone, pale grey thin-bedded fine-grained about

8

(c) Limestone, pale grey, with several thick shell bands with E. lobata aff. laqueata, G. edelburgensis, Pugilis pugilis; a band about 2 ft from base with Lithostrotion junceum, Lonsdaleia floriformis floriformis, Palaeosmilia regia

25

(b) Limestone, pale grey to grey-white, very crinoidal, with scattered pockets of shells; Antiquatonia hindi wettonensis, Avonia youngiana, E. lobata aff. laqueata

23

(a) Limestone, dark grey crinoidal, paler coloured at top; scattered chert nodules, a few shells

4.5

The above beds form a transition between the normal dark facies of the Eyam Limestones and the easternmost of the two large flat reefs noted above. A complete lateral passage into reef-limestone takes place within some 50 yd to the south-east. In the middle of the quarry (loc. 106) [SK 2365 7459] the flat reef consists of about 75 ft of pale massive crinoidal and shelly limestone with some finer grained bands. The fauna includes Alitaria panderi, Antiquatonia insculpta, Avonia youngiana, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata and K. spinulosa.

The lowest part of the Eyam Limestones is present in Coombsdale Quarry. A section [SK 2330 7478] in the middle part of the quarry (loc. 107) is as follows:

feet

(f) Limestone, dark cherty, with shaly bands near base

4.5

(e) Limestone, grey crinoidal (knoll-reef passing westwards into about 2 ft of dark limestone); A. cf. insculpta, E. lobata aff. laqueata

(d) Limestone, dark thin-bedded cherty, shelly in places, especially near top; A. cf. insculpta, Productus productus

17

(c) Shale, dark calcareous about

0.25

(b) Coal, bright 0.5 in

thin

(a) Seatearth, buff

0.25

Monsal Dale Beds

The shale/seatearth parting is of variable thickness, being as little as 2 inches in all only some 10 yd north-east of this section. At the eastern end of the quarry an 8-in parting of dark calcareous shale is present above item (e). The latter passes laterally into pale rubbly limestones forming the northern edge of a knoll and these yield (loc. 108): Avonia cf. thomasi, A. youngiana, E. lobata aff. laqueata, G. edelburgensis, G. cf. giganteus inflatus and P. productus. To the west of the main section dark-bedded cherty limestones only are developed. Here Green and others (1887, pp. 21–2) noted the following section at the base of the Eyam Limestones:

feet

inches

"Bright clean coal

2

Light-grey fireclay

1

6

Yellowish sandy clay, with a thin layer of oxide of iron at the bottom.

3"

The presence of the coal was confirmed by Morris (1929, p. 55) who stated that it reached 6 inches in the Coombs Dale area. He also (ibid., p. 49) recorded a thin shale with "fish spines and an abundance of Cladochonus sp. " above the coal. This is the shale at the base of the Coombsdale Quarry section (loc. 107) given above.

To the north and west of Coombsdale Quarry the Eyam Limestones outcrop narrows greatly owing to overlap by Namurian shales and beyond a point [SK 2283 7489] about 0.25 mile W. of the quarry the Eyam Limestones are completely cut out.

To the south-west of Calver Peak a small outlier of Eyam Limestones flat reef occurs and part extends into the present district. The sectionTop of section [SK 2246 7422] just south of southern edge of district. on the east side of the tributary to Coombs Dale (loc. 77, bed g; see also p. 82) shows 5.5 ft of pale brown roughly bedded limestones with A. antiquata, Echinoconchus punctatus, Eomarginifera lobata laqueata, K. spinulosa, P. productus hispidus and S. sp. latissimus group resting on the Monsal Dale Beds.

To the north of Coombs Dale, two outliers of Eyam Limestones flat reef are present on High Fields. An area of small exposures some 80 yd across (loc. 109) [SK 2159 7490] yielded Antiquatonia hindi, A. insculpta, Avonia davidsoni, A. thomasi, A. youngiana, Dielasma hastatum, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata, Girtyella sacculus, Pleuropugnoides pleurodon, Pugnax pugnus and Schizophoria resupinata. Farther to the west, a third outlier, on Moisty Knowl, shows a small thickness of dark cherty limestones. An excavation [SK 2090 7511] showed 3 ft of beds of this type.

Middleton Dale and The Cliff

On the western outskirts of Stoney Middleton [SK 2269 7536] the Eyam Limestones appear from beneath the Namurian cover. Between Shining Cliff and Stoney Middleton dark beds at the base form steep grassy or wooded slopes above the cliffs of Upper Monsal Dale Beds. The overlying flat reef forms a feature on the northern lip of the dale.

In Stoney Middleton the following section (loc. 76) [top at 2300 7550] continues that given on n. 80:

feet

(s) Limestone, grey: Aulophyllum fungites pachyendothecum (fide Morris 1929, p. 54), Dibunophyllum bipartitum craigianum and D. bipartitum konincki

1.25

(r) Limestone, dark cherty, thin-bedded

10

(q) Limestone, grey-brown finely granular

3.25

(p) Limestone, dark thin-bedded often wavy-bedded cherty, some shale partings up to 3 in

21

(o) Clay parting on potholed surface (potholes up to 1 ft deep, filled with clay)

0 to 0.25

Monsal Dale Beds

The coral band lies at the base of the flat reef and appears to be a local development only.

Farther west the Castle Rock section (loc. 75, see also p. 79) [top at 2245 7583] is continued upwards in the Eyam Limestones as follows:

feet

(dd) Limestone, pale massive fossiliferous, with some coarse crinoid debris (flat reef); A. hindi wettonensis, 'B.' planicostata, P. productus hispidus

6

(cc) Limestone, pale, much pale chert; few fossils

6

(bb) Not exposed (flat reef)

5

(aa) Limestone, dark (poorly exposed)

about 40

Monsal Dale Beds

To the north-east of this section flat-reef limestones form an extensive outcrop with a steep dip-slope, near the junction with the Namurian; the dip may have a slight depositional element. The maximum thickness of the flat reef is of the order of 100 ft. Farther west, dark limestones of the Eyam Group overlie the Monsal Dale Beds of the Shining Cliff section.

In Furness Quarry the section (loc. 73) top at [SK 2100 7608], continues that of p. 75:

feet

(z) Limestone, dark thin-bedded, with shaly partings and thin rather regular bands of chert; gastropods and Gigantoproductus spp.

14

(y) Clay, grey rusty-weathering (thinning to south)

0.5 to 1.25

Monsal Dale Beds

Eyam and Foolow

The upper part of Eyam Dale provides an excellent section (loc. 110) of the Eyam Limestones top at [SK 2200 7634]:

feet

(j) Limestone, light grey thin-bedded; A. cf. insculpta

4

(i) Limestone, dark thin-bedded cherty; 3-ft coral band (Eyam Dale Coral Band) at 6 ft from top; D. bipartitum bipartitum, D. bipartitum craigianum, D. bipartitum konincki

10

(h) Limestone, grey to dark grey thin-bedded cherty

1.25

(g) Limestone, dark grey to grey massive slightly crinoidal, with a little chert

9.5

(f) Limestone, brownish grey thin-bedded

4

(e) Limestone, dark fine-grained thin-bedded; 9-in shelly band at 3.75 ft from base

8

(d) Limestone, grey finely crinoidal

1.25

(c) Limestone, dark fine-grained thinly and irregularly bedded, cherty; G. giganteus, G. sp. edelburgensis group

10

(b) Limestone, grey to pale grey cherty; scattered shells and a 1-ft shell band at 1.25 ft from base; G. giganteus cf. crassus, P. productus hispidus

6.5

(a) Limestone, dark fine-grained poorly bedded, with irregular chert

9.5

The lowest beds are some 10 ft above the base of the Eyam Limestones while the highest are a few feet below the base of the flat reef (see p. 98). A good section of the latter is in an old quarry [SK 2208 7623]: pale grey even-and thin-bedded fine-grained to finely crinoidal limestone, more crinoidal and shelly at base and with some chert, 10 ft.

To the north of Eyam, the Eyam Limestones have been found underground in two places in a crosscut joining Glebe and Ladywash shafts (Dunham 1952, p. 86). Pale massive shelly and crinoidal reef (probably flat reef) limestones at the base of the group were passed through in the vicinity of the intersection with the Old Edge Vein [SK 2194 7696] to [SK 2203 7721]; these are overlain by dark cherty limestones south-east along Old Edge Vein [SK 2210 7704]. North of here a gentle southerly dip takes the base of the Eyam Limestones above the crosscut but they reappear at the Ladywash end where, 38 yd from the shaft, the roof of the crosscut shows dark fine-grained cherty limestone with limestone pebbles in lowest 2 to 3 in, resting on a thin clay parting over pale fine-grained limestones of the Monsal Dale Beds (see p. 95). By Ladywash Shaft (loc. 111) [SK 2189 7754] the lowest beds of the Eyam Limestones yielded Avonia aff. davidsoni and P. productus hispidus. In Eyam village the Eyam Limestones are about 125 ft thick and include about 40 ft of flat reef at the top. Underground, progressive erosion at the base of the Narnurian occurs and at Ladywash Shaft some 30 ft only of dark thin-bedded limestones are present (Dunham ibid., p. 86).

To the west and south-west of Eyam the lower, dark limestones show a progressive increase in thickness. Correspondingly the base of the flat reef appears at higher and higher horizons and it disappears altogether about half a mile west of the village. All but the lowest beds of the dark limestone pass laterally into grey limestones, the passage taking place along a sinuous line running in a general south-westerly direction from Eyam View. Small knoll-reefs are present at two horizons, the lower at the base of the Eyam Limestones near Hanging Flat [SK 203 761] and on the west side of Cucklet Dale [SK 215 761]. The higher knolls, four in number, lie in the grey limestones between Linen Dale and Eyam View. Their disposition shows a close geographical relationship to the flat reef.

Linen Dale shows a long section of part of the lower dark limestones overlain by grey limestones. The upper end of the dale provides a cross-section of a knoll whose base lies in the dark beds about 6 ft below the gigantoproductoid band noted below, but which extends upwards into the grey limestones. This knoll was first described by Morris (1929, pp. 49–50 and 52). A section (loc. 112) [SK 1984 7688] near Waterfall Farm showed 25 ft of pale massive Shelly and crinoidal reef-limestone with Alitaria panderi, Antiquatonia hindi, A. hindi wettonensis, A. insculpta, A. cf. sulcata, Avonia thomasi, A. youngiana, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata, Girtyella? sacculus and K. spinulosa. The total height of the knoll is about 35 ft. On the northern flank of the knoll (loc. 113) [SK 1989 7689] the following beds are exposed:

feet

(e) Limestone, grey to dark grey finely granular

4

(d) Not exposed

4

(c) Limestone, pale grey-brown, thinly but irregularly bedded; Alitaria panderi, Antiquatonia cf. insculpta, Avonia thomasi, A. youngiana, Pugnax pugnus [small form]

3

(b) Limestone, grey-brown fine-grained

6.5

(a) Limestone, grey; abundant large shells; A. cf. hindi, Gigantoproductus edelburgensis, G. sp. cf. gigantoides

5

The lowest item passes laterally into the knoll; the higher beds appear to thin and to pass upwards over it, though some lateral passage into the knoll in the lowest part of these beds cannot be excluded.

A more extensive section (loc. 114) of the beds above the gigantoproductoid bed (a) was measured [SK 1988 7693] on the western side of Linen Dale:

feet

(g) Limestone, dark grey thin-bedded fine-grained, with bands of chert up to 11 in thick

10.5

(f) Limestone, grey irregularly bedded fine-grained; some chert in middle and at top

(e) Limestone, pale brown crinoidal (some columnals up to 1-in diameter); lowest 6 in thin-bedded; L. floriformis floriformis and brachiopods including A. cf. insculpta

4

(d) Limestone, grey to dark grey fine-grained, with a little chert

5.75

(c) Not exposed

2

(b) Limestone, grey fine-grained

3

(a) Limestone (gigantoproductoid bed of previous section) dark grey, with G. sp. cf. gigantoides

2

Near the junction with the Namurian, a large sink-hole (loc. 115) [SK 1988 7704] northwest of Waterfall Farm showed the following section:

feet

(f) Limestone, grey to dark grey thin-bedded cherty; a 2-ft coral band 4 ft from base, with A. fungites pachyendothecum, D. bipartitum craigianum, D. bipartitum konincki

9.5

(e) Limestone, pale grey-brown crinoidal ; Avonia thomasi, E. lobata aff. laqueata

6

(d) Limestone, dark grey thin-bedded cherty, paler at top

4.5

(c) Limestone, dark grey massive cherty; very cherty in lowest 2 ft; shell band 3.5 ft, 5 ft from base with G. giganteus

15

(b) Limestone, dark grey thin-bedded very cherty

5

(a) Limestone, dark grey thickbedded, with a little chert

14.5

To the north of the last section, the Eyam Limestones have been proved, beneath Namurian cover, in the Hucklow Edge No. 2 Borehole (loc. 103) [SK 2025 7760];

Thickness

Depth

feet

inches

feet

inches

Base of Namurian

265

6

Limestone, pale brown crinoidal

1

0

266

6

No core

8

5

274

11

Limestone, pale grey to pale brown, very cherty in top 2 ft 5 in and with irregular silicification below

3

10

278

9

Limestone, pale grey to grey with some darker coloured bands and bioclastic bands

5

3

284

0

Limestone, buff to pale grey with some darker bands, mostly fine-grained but with some finely bioclastic bands, some chert; Lithostrotion junceum at 294 ft 8 in

20

8

304

8

Limestone, blue fluoritized

8

305

4

No core

12

1

317

5

Limestone, mainly dark grey, with some paler bands; silicified and with bands of chert in places above 329 ft 9 in

27

1

344

6

Monsal Dale Beds (see p. 93)

Water Grove and Burnt Heath

To the south of Middleton Dale the Eyam Limestones, some 120 ft in thickness, occupy a broad tract extending from Burnt Heath to Water Grove. The dark limestones at the base are present as far as the south-eastern extremity of this outcrop, but disappear by lateral passage into the overlying grey limestones south and south-east of Castlegate Farm. The section at Cavendish Mill [SK 2054 7530] (see also p. 83) showed 4 ft of dark cherty limestone resting on the Monsal Dale Beds. To the south of Castlegate Farm two knoll-reefs are present at the base of the Eyam Limestones. One of these, some 14 ft in height, (loc. 166) [SK 1953 7503] showed pale fine-grained poorly bedded reef-limestone, crinoidal in places, and with Antiquatonia hindi, A. hindi wettonensis, A. insculpta, A. sulcata, Avonia thomasi, A. youngiana, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata and Girtyella ? sacculus. Farther south, three knoll-reefs (one largely beyond the southern edge of the district) occur as outliers resting on the surface of the Monsal Dale Beds.

To the west of Castlegate Farm the outcrop of the Eyam Limestones is concealed by the shale outlier of Wardlow Mires. The lowest, dark beds are, however, seen in the axis of a sharp N.N.W.–S.S.E. anticline which crosses the main road between Water Grove and Housley. The following section (loc. 117) [SK 1911 7583] was measured on the north side of the road:

feet

(h) Chert, pale brown [SK 1902 7581]

1

(g) Not exposed

2

(f) Limestone, buff fine-grained much silicified; some shells; corals at base

4

(e) Limestone, dark

12

(d) Limestone, grey massive

2

(c) Limestone, pale grey-brown crinoidal: D. bipartitum konincki, L. junceum, Palaeosmilia cf. murchisoni, P. sp. [cerioid form ?].

3.5

(b) Limestone, pale grey-brown crinoidal; shelly in top 3 ft and with Lithostrotion junceum and Lonsdaleia floriformis floriformis; 2 ft very coarsely crinoidal 31 ft from base; finely crinoidal in lowest 3 ft

11

(a) Limestone, dark fine-grained irregularly bedded ('hackly'); some paler variegation towards top; some large crinoid stems in upper half

1.75

Item (a) marks the top of the lowest dark limestones; these form three inliers (the northern two being small in extent) along the axis of the anticline. Information from a section of Watergrove Sough shows the coral band (c) to lie some 80 ft above the base of the Eyam Limestones. It is uncertain whether this represents the Eyam Dale Coral Band, the underlying beds having expanded, or whether it is at a higher horizon.

Wardlow Mires and Great Hucklow

Just to the west of Wardlow Mires poorly exposed dark limestones at the base of the Eyam Limestones overlie the Monsal Dale Beds of the Cressbrook Dale section [top at 1788 7550] (see also p. 83). Wardlow Mires No. 1 Borehole (loc. 101) [SK 1850 7553] proved the overlying Viséan shales to 82 ft 10 in (see p. 91). The shales rested, with slightly irregular base, on dark thin-bedded limestones of the Eyam Limestones. These beds had frequent mudstone partings in their upper part and were cherty below: Lingula, Orbiculoidea and small trilobites were common, Lingula especially so in the shale partings. The Eyam Limestones rested on an irregular surface of Monsal Dale Beds at 1131 ft with a 3-in mudstone with fish debris at the junction. Wardlow Mires No. 2 Borehole (loc. 102) [SK 1825 7586] (see p. 378) showed a closely comparable section, though here a 0.5 in carbonaceous band was present in addition, in the mudstone parting at the base.

When traced north from Wardlow Mires the lower, dark beds persist along Silly Dale at least to a point 0.25 mile south of Grindlow where higher beds come in. However, on the western edge of the outcrop near Stanley Lodge the grey lithofacies extends rapidly downwards to the base of the Eyam Limestones. From here to Great Hucklow all the exposed part of the Eyam Limestones is grey.

The section in Silly Dale shows the uppermost part of the lower, dark limestones overlain by the grey. A small knoll-reef is present at the base of the grey limestones on the west side of the dale, at the south end [SK 181 766]. At the northern end of the valley a section (loc. 118) [SK 1818 7697] at about the same horizon, is as follows:

feet

(e) Limestone, pale shelly, with a little chert

2.75

(d) Limestone, grey, cherty and with some dark bands in upper part; abundant L. junceum, some silicified, in lowest 3 ft

7

(c) Limestone, dark bituminous

11

(b) Limestone, grey to pale grey well-bedded finely bioclastic; some shells

2.5

(a) Limestone, dark bituminous

2

By comparison with the record of the Great Hucklow Borehole (see below) the coral band lies 61 ft above the base of the Eyam Limestones and is correlated with the Eyam Dale Coral Band.

Between Foolow and Grindlow a series of 6 knoll-reefs, up to some 20 ft in height, is present at or near the top of the Eyam Limestones. The larger of these (up to 450 yd in length) showed a N.W.–S.E. orientation. At Great Hucklow [SK 175 778] another, apparently unorientated, knoll-reef is present at a similar horizon.

The Great Hucklow (No. 7) Borehole [SK 1777 7762] (see also p. 94) showed the following generalized section:

feet

'Clay and stones'

8

Limestone, cherty, mainly pale but with 4 ft of dark limestone at 16 ft and 5 ft of dark limestone at 35 ft; 3 ft dark and non-cherty at 49 ft

85

Limestone, dark cherty; thin shale band at base

129

Limestone, pale, with a little chert

143

Limestone, dark cherty, with shale partings

146

Monsal Dale Beds

The general division into upper pale and lower dark limestones holds here, but there are also signs of the incoming (129 to 143 ft) of pale limestones near the base.

Little Hucklow and Bradwell

To the north of High Rake the grey lithofacies of the Eyam Limstones (see p. 32) extends for a short distance only, and then the subdivision consists of dark cherty limestones, with small knolls in places. One of the latter, elongated N.W.–S.E., and lying at about the same horizon as the Grindlow knolls, is developed on Broad Low.

Exposures of the dark beds are in general poor. A section [SK 1702 7819] north-east of Poyntoncross House shows dark fine-grained limestone, cherty and with lenses of grey limestone up to 1.5-ft thick with many corals. These beds appear to pass rapidly eastwards into limestones of the grey lithofacies. To the north of Great Hucklow the Derwent Valley Water Board Broad Low (No. 6) Borehole [SK 1753 7821] (see also p. 94) passed through the full thickness of the Eyam LimestonesInformation from the examination of cutting samples by Professor F. W. Shotton.:

Thickness

Depth

feet

feet

Landslip and Edale Shales

25

25

Limestone, pale to dark grey, with 10 in of chert and some black shale

5

30

Limestone, white

17

47

Limestone, grey to black shaly

3

50

Limestone, pale grey very cherty

79

Limestone, dark grey cherty

26

105

Limestone, pale grey, with rare chert

10

115

Limestone, pale grey to black, some chert

17

132

Shale, black about

1

133

Monsal Dale Beds

The record appears to show beds transitional between the grey and dark lithofacies.

The Little Hucklow Borehole [SK 1684 7863] showed the following section:

Thickness

Depth

feet

feet

Soil

1

1

Limestone, black cherty

7

8

Limestone, grey, with dark chert; some dark shale partings near base

14

22

Limestone, black cherty, dark shale partings near base

11

33

Clay, brown (fide driller)

1

34

Monsal Dale Beds (see p.94)

A little to the north of Nether Water a large knoll-reef is present in the upper part of the Eyam Limestones. The knoll has been cut through in Stanlow Dale, in all but the southernmost sections, to show the underlying dark limestones. Dips suggest that the knoll is composite and that two knolls, on the east and west sides of the dale respectively, have coalesced. Shirley and Horsfield (1940, p. 288) recognized the presence of this knoll and recorded a fauna as follows: "Productus (Gigantella) sp., P. (G.) auritus Phillips, P. (G). latissimus Sowerby, P. hindi Muir-Wood, Spirifer aff. bisulcatus Sowerby and occasional specimens of Caninia".

To the west of the main outcrop of the Eyam Limestones an outlier of knoll-reef is present near Intake Farm. A section (loc. 119) [SK 1641 7956] 150 yd N. of the farm shows nearly the whole thickness: pale very crinoidal limestone with columnals up to 1 inch in places, Shelly with Acanthoplecta mesoloba, Alitaria panderi, Antiquatonia hindi, A. insculpta, Avonia davidsoni, A. thomasi, A. youngiana, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata, G.? sacculus, Plicochonetes buchianus and Spirifer (Fusella) triangularis. An almost identical fauna was obtained from an exposure (loc. 120) [SK 1646 7965] at the north-eastern end of the knoll.

To the north of the main Tideswell–Bradwell road an extensive flat reef is developed within the Eyam Limestones, and to the north of an east–west line through Hartlemoor Farm this occupies the whole of the subdivision. Dark limestones below the flat reef are exposed near the junction of Jenning's Dale and Green Dale [SK 1698 7992] where "230 yd west of the farm" (Hazlebadge Hall) Shirley and Horsfield (1940, pp. 286, 288) record a fauna including "Cyathaxonia cornu, Zaphrentis enniskilleni derbiense, brachiopods and Phillipsia sp. "

The relations of dark limestones to the flat reef are most easily observed in Bradwell Dale. A section on the east side of this valley at the south end shows a small development of flat reef overlying the Monsal Dale Beds. The flat reef first grew strongly upwards and later spread laterally at a horizon some 30 ft above the base of the Eyam Limestones. The total thickness of the flat reef here is about 130 ft, of which the lowest 75 ft are exposed in the dale side; the uppermost beds are well seen farther east in the side of a fluorite working [SK 1731 8035] where they are often very coarsely crinoidal. At the southern end of the dale, the continuation of the section (loc. 99) [SK 1714 8039] of p. 89 is as follows:

feet

(h) Limestone, dark bituminous, passing northwards into flat reef; brachiopods, gastropods and the fish Petalodus acuminatus

6.5

(g) Limestone, pale fine-grained shelly; Alitaria panderi, Antiquatonia cf. antiquata, A. insculpta, E. lobata laqueata and K.  spinulosa

22

Monsal Dale Beds

The section shows both flat reef and normal dark facies and closely matches that on the east side of the dale.

At the north end of the dale the section (loc. 100) [SK 1741 8077] given on p. 89 is continued by flat reef as follows:

feet

(l) Limestone, pale crinoidal, massive in lowest 7 ft, more thin-bedded above; Acanthoplecta mesoloba, Antiquatonia hindi, A. hindi wettonensis, A. insculpta, E. punctatus, K. spinulosa, Pleuropugnoides pleurodon, Pugnax pugnus

11

Brook House

A narrow outcrop of beds referred to the Eyam Limestones on faunal grounds is present along the Viséan–Namurian junction west of Water Swallows. This outcrop is bounded on the east by the Miller's Dale Beds and on the west by the Namurian as is that of the Monsal Dale Beds at Dove Holes. The two outcrops, however, are separated by an east–west fault of pre-P2 age and the relations of the two are shown in (Figure 7).

The greater part of the Eyam Limestones of this area, some 30 ft thick, are dark, thin-bedded and cherty. A quarry [SK 0716 7602] near Blackedge Farm showed 15 ft of grey to dark grey fine-grained thin-bedded cherty limestone with small brachiopods and occasional corals. Farther south, the section (loc. 121) [SK 0690 7534] is as follows:

feet

(h) Limestone, dark well-bedded fine-grained cherty; rare corals, Cyathaxonia sp. cornu/rushiana group, Rotiphyllum aff. rushianum

2

(g) Limestone, as above; abundant corals; Aulophyllum fungites cumbriense, Caninia sp. nov.aff. buxtonensis, D. bipartitum bipartitum, D. bipartitum konincki, Koninckophyllum interruptum, K. magnificum

1

(f) Limestone, grey to dark grey thin-bedded (beds up to 5-in thick); corals above 5 in from base; Aulophyllum fungites cumbriense, Dibunophyllum bipartitum bipartitum, D. bipartitum craigianum, D. bipartitum konincki, Diphyphyllum fasciculatum, Alitaria panderi

1.25

(e) Limestone, grey to dark grey shelly and crinoidal; Alitaria panderi, Avonia thomasi, A. youngiana, E. lobata laqueata, K. spinulosa, P. productus hispidus , S. (F.) triangularis

0.5 to 1.75

(d) Limestone, grey well-bedded

1

(c) Clay parting

up to 0.25

(b) Limestone, grey well-bedded

2

(a) Limestone, dark grey-brown finely crystalline cherty; Aulophyllum fungites cumbriense, D. bipartitum bipartitum, G. giganteus crassus throughout; A. fungites cumbriense, D. bipartitum konincki, Alitaria panderi, Avonia youngiana, Pugilis pugilis in pocket at 2 ft from base

6

The section shows the highest exposed post-D1 strata in the vicinity.

Near Brook House a lenticular mass of knoll-reef limestone makes its appearance at the base of the Eyam Limestones and thickens southwards. The section (loc. 122) [SK 0673 7484] is as follows:

feet

(d) Limestone, grey-brown irregularly bedded shelly; Alitaria panderi, Antiquatonia antiquata, A. hindi, A. insculpta, Avonia thomasi, A. youngiana, K. spinulosa

5.5

(c) Limestone, grey to dark grey massive fine-grained

2.5

(b) Limestone, grey, darker towards base, shelly throughout and with corals in top 6 in; D. bipartitum bipartitum, Productus productus hispidus

8

(a) Limestone, grey-brown massive (knoll-reef); Acanthoplecta mesoloba, Antiquatonia antiquata, A. hindi, A. insculpta, Avonia davidsoni, A. thomasi, A. youngiana, Echinoconchus punctatus, Eomarginifera lobata aff. laqueata, G. ? sacculus, K. spinulosa, S. (F.) triangularis, Sudeticeras sp.

30

The last item represents about the full thickness of the knoll-reef.

Shales of P2 age

These beds are known in the shelf area only from the Wardlow Mires outlier. Material from a trench (loc. 124) [SK 1892 7540] collected by Dr. J. Shirley, showed a probable P2 fauna with Chonetes sp. [s.l.], Crurithyris sp., Posidonia corrugata and Weberides cf. mailleuxi. Similar shelly mudstones are known from the tips of Water-grove Mine (loc. 123b) [SK 1882 7577] and from a 13-ft excavation [SK 1810 7558] at Wardlow Mires. In the Wardlow Mires No. 1 Borehole (loc. 101) [SK 1850 7553] (see also p. 102) the base of the Namurian is considered to be at a depth of 67 ft 9 in. The Namurian is underlain by P2 shales extending to the slightly irregular junction with the Eyam Limestones at 82 ft 10 in. Sudeticeras cf. stolbergi Patteisky occurred at 80 ft 1 in. Wardlow Mires No. 2 Borehole (loc. 102) [SK 1825 7586] proved a closely comparable section of P2 shales. Here the recognition of Cravenoceras leion Bisat provided a clear base to the Namurian at 65 ft 4 in and the shales extended down to a depth of 77 ft 7.5 in.

Marginal Province

The apron-reef

Perryfoot and Windy Knoll

The westernmost exposures of apron-reef limestones lie 0.25 mile N. of Sparrow Pit. Here the apron-reef is narrow but, traced north-eastwards, it expands laterally to an average width of some 300 yd. The steep frontal slope is normally well developed and shows dips of from 15°-30°. A line of sink-holes is present at the junction of the apron-reef and the Namurian and most of these show good sections of the upper part of the reef.

Perry Dale shows a cross-section of the apron-reef. On the inward side, the algal reef is well developed to the south-west of the dale [SK 1021 8102] to [SK 1029 8110] where differential erosion has caused it to stand out. The algal reef has a maximum width of about 90 ft and a minimum height of about 60 ft, the base not being seen. A lesser development of the algal reef is present on the north-east side of the dale. Fossiliferous fore-reef limestones (see also (Table 5), p. 142) are exposed between the algal reef and the large sink-hole by Tor Top. The latter (loc. 126) [SK 0989 8126] shows the following generalized section:

feet

(b) Limestone, pale massive reef-type, with coarsely crinoidal pockets and shelly patches, matrix fine-grained; large reef fauna including Goniatites sp. crenistria group

20

(a) Limestone, darker and finer-grained than above; large reef fauna including Product us productus cf. hispidus, abundant Streblopteria laevigata and Beyrichoceras sp. (rectangularum or delicatum)

18

The upper item (b) is of P1a age from the goniatite evidence, and is indicated separately on (Plate 11).

Over the half-mile stretch of apron-reef north-east of Perryfoot typical exposures [SK 1014 8144] and [SK 1078 8177] occur in the sinkholes at the limestone edge. An exposure [SK 1059 8146], near the Bull Pit, shows a poorly developed algal reef at the inner margin of the apron; this was noted by Wolfenden (1958, p. 877) who considered that it belonged to the lower of the two levels of algal reef development recorded by him. The present mapping, however, would suggest that this algal reef is at a stratigraphically higher level than that of Perry Dale. The algal reef is also exposed at the top of Snels Low [SK 1134 8178] and in the small valley [SK 1159 8205] between the same feature and Middle Hill. The width of the algal reef in all these occurrences does not appear to exceed 20 ft.

The valley between Snels Low and Middle Hill shows a good cross-section of the apron-reef between the algal reef (see above) and the outer edge [SK 1154 8224]. The section shows the normal flattening of the dip on the inward side and a frontal dip of 20 degrees at the north (outward) end. A rich fauna has been obtained (loc. 127) here though no goniatites were found.

On Middle Hill and Peaks HillNot named on six-inch or one-inch maps though the name is used in literature. [SK 118 827] the structure of the apron-reef is more complex than is usually the case. The normal apron relationships are shown on Middle Hill, with small occurrences of algal reef on the inward side and strong frontal dips (see (Plate 11)). At the point where the latter develop there is a well-defined valley in which Giant's Hole [SK 1194 8268] lies and north-west of this lies Peaks Hill which appears to 'adhere' to the outer margin of the reef. The slopes on the southern side of the Giant's Hole valley yield a reef-fauna which is not diagnostic of age (locs. 132–3, see (Plate 11) and (Table 5), p. 142) though Parkinson (1943, p. 126) records a high B2 fauna with Goniatites aff. crenistria and G. maximus from "Middle Hill" and the same author (1947, p. 107) lists the following goniatites from "the vicinity of the gorge" by Giant's Hole: Beyrichoceras aff. delicatum, Beyrichoceratoides sp., Bollandoceras aff. micronotum, Goniatites hudsoni group, G. aff. antiquatus Bisat and G. aff. maximus Bisat.

Peaks Hill itself is formed of a knoll-like mass of reef-limestones elongated parallel to the reef margin and showing quaquaversal dips. These beds have yielded (loc. 130) [SK 1176 8267] the goniatites Goniatites crenistria [early form] and G. cf. hudsoni indicative of the uppermost part of B2. A nearby exposure (loc. 128a) [SK 1170 8267] yielded Goniatites wedberensis Bisat in addition (see also p. 149). The exposure (loc. 131) [SK 1179 8266] on the south side of Peaks Hill with Palaeosmilia regia was first noted by Shirley and Horsfield (1940, p. 279). The relations of Peaks Hill to the main mass of the apron-reef are here attributed to uplift in late B, times along and parallel to the reef margin with the consequent offsetting of the later part of the apron-reef in relation to the earlier. The unusually high inward dips at Peaks Hill would thus be interpreted as a reflection of the uplift. As noted elsewhere (p. 162), late Viséan movements in the neighbouring limestone salient near Mam Tor appear to have been particularly acute.

On the eastern side of Middle Hill the reef margin swings northwards and at Windy Knoll the apron-reef is entirely concealed by the Namurian. A small outcrop [SK 1253 8292] of algal reef is present a little south of the latter locality.

Treak Cliff and Winnats

In this area the apron-reef occurs as a belt trending N.N.W.–S.S.E. At the northern end it makes a westward turn, just before disappearing under the Namurian, which suggests a junction at depth of the two outcrops of apron-reef on the sides of the D1 salient near Mam Tor.

On Treak Cliff the inner margin of the reef-complex is well marked by the presence of a number of well-developed algal reefs (Wolfenden 1958, p. 879). The most northerly of these lies close to the shale boundary and is noteworthy as the locality [SK 1328 8334] where Shirley and Horsfield (1940, p. 280) recorded signs of unconformity at the junction of reef and standard limestone. Wolfenden's confirmation of Parkinson's (1953, p. 254) contention that the apron-reef passed laterally into limestones of the standard sequence makes it likely that any break at this locality is more of the order of a non-sequence; small Neptunian dykes filled with crinoidal limestone are evidence of this in the algal reef.

The best developed of the algal reefs forms the crest of Treak Cliff (Plate 13A) [SK 1343 8322] to [SK 1345 8283]. This has been found by Ford (1964, pp. 31–2) to be considerably wider than stated by Wolfenden (ibid., pp. 876–7) being at its maximum some 250 ft across; the height is given as 50 ft. The general characters of the algal reefs are described on p. 18 and the Treak Cliff occurrence is typical. Apart from the characteristic stromatolitic algae, sponges and pockets of small reef brachiopods occur (loc. 136c–k), and at a point (loc. 136h) [SK 1344 8298] nearly 0.25 mile S.E. of Blue John Cavern entrance colonies of Lirhostrotion martini and L. pauciradiale up to 6 ft across and in the position of growth are to be seen. Some 5 to 10 yd N. of this locality Dibunophyllum bipartitum and a restricted fauna of reef brachiopods were collected. Original cavities between algal colonies have been filled with calcite in a characteristic cuspate form.

The highly fossiliferous fore-reef limestones of Treak Cliff show outward dips of from 25° to 35°. The essentially depositional nature of these was stressed by Shirley and Horsfield (1940, pp. 288–9) and this has been recently confirmed by Broadhurst and Simpson (1967, pp. 443–8) by demonstrating that shells and limestone cavities showed horizontal or near horizontal sedimentary infillings. One example is an orthocone nautiloid obtained [SK 1329 8344] near the Odin Mine. The most marked change across this belt is the increase in the amount of crinoid debris; on the lower slopes some of this is quite coarse e.g. [SK 1365 8300]. The results of detailed collecting across the outcrop are summarized on p. 150. This area has formed the basis of most of the previous references to the Castleton area. Bisat (1934, pp. 285–6) records a goniatite fauna with Bollandites castletonensis (Bisat) from Treak Cliff, and Shirley and Horsfield (1940, p. 279) noted Goniatites cf. hudsoni. These records indicate an upper B2 age for the fore reef here. A fauna indicative of the top of the zone was obtained by Parkinson (1947, p. 107; 1953, p. 258) from coarsely crinoidal limestones above the 'Odin Fissure' [SK 1342 8345]; this included Goniatites crenistria and Beyrichoceratoides truncatus Phillips sp. (see also loc. 135, p. 149). Ford (1952, p. 353) recorded Goniatites maximus from a point [SK 1353 8303] underground in the Treak Cliff Cavern. Parkinson (1952, p. 201) has described a thin lenticular bed with abundant Dielasma hastatum from near the summit of Treak Cliff apparently within the algal reef [SK 1343 8317].

In the Winnats gorge the transition from shelf facies to apron-reef is well seen. Here Wolfenden (1958, pp. 875–6) recognized the presence of a lower algal reef somewhat inside (geographically) the position of the upper algal reef of Treak Cliff. The present work confirms the presence of the lower algal reef [SK 1350 8270], though it appears more nearly in line with the upper than shown by Wolfenden.

Long Cliff and Goosehill

On the slopes between Long Cliff and Goosehill the apron-reef dips northwards at from 15° to 32°. On the inner side an algal reef has been recognized in this tract only at Longcliff Plantation [SK 1410 8226], though it is less well developed than at Treak Cliff. On the outer side the apron-reef is overlain by Beach Beds as far east as Goosehill but beyond here dark limestones of basin facies rest on the apron-reef (see p. 110).

The best cross-section of the fore reef is provided by the gully below Cow Low (Cow Low Nick). This contains, at a point (loc. 138) [SK 1420 8241] about half way down, a pocket (about 1.5 ft x 4 ft) of fine-grained limestone crowded with goniatites. The occurrence was first noted by Bisat (1934, p. 291). Ford (1965, pp. 186–91) lists the fauna of which Beyrichoceras rectangularum, Bollandoceras submicronotum (Bisat) and Goniatites maximus are the commonest forms with less common B. vesiculiferum (de Koninck) and Prolecanites cf. P. discoides (Foord and Crick); the age is upper B2. Ford has suggested that the goniatite lens accumulated in a surge channel or submarine cave in the fore reef.

On Cow Low, an exposure [SK 1427 8235] near the inner edge of the apron-reef shows tuffaceous limestone. This is interpreted as indicating a former extension of the nearby outcrop of the Lower Lava into the reef-belt.

At Goosehill, massive fore-reef limestones are well seen, though inaccessible, in the gorge [SK 1487 8263] below Peveril Castle. This shows a vertical cliff of some 300 ft in these beds. Shirley and Horsfield (1940, p. 279) recorded Goniatites maximus "from the slopes above Goosehill".

Cave Dale and Siggate

The section in Cave Dale shows the transition from apron-reef to standard limestones. At the junction there is no algal reef and the transition appears to take place by interdigitation of the two facies in the lowest part of the dale. At a higher horizon, however, the apron-reef overlies limestones of shelf facies indicating a slight inward movement of the apron as it built up.

The apron-reef is well seen in the quarry [SK 1507 8267] at the entrance to Cave Dale which shows some 40 ft of poorly-bedded fossiliferous limestone. No diagnostic fossils have been obtained from this exposure.

Between Cave Dale and Siggate the frontal slope of the apron-reef is well developed with dips of 15° to 23° (Plate 12A). As at Treak Cliff, the beds at the foot of the apron are commonly crinoidal e.g. [SK 1559 8260]. From a roadside exposure [SK 1587 8248] on Siggate, Parkinson (1947, p. 110) recorded Goniatites crenistria and Beyrichoceratoides truncatus (or a near form) indicative of a low P1a horizon. The goniatites listed as G. crenistria by Parkinson have been re-identified as G. maximus, indicating an upper B2 age (Smith and Yü 1943, p. 49). Shirley and Horsfield (1940, p. 279) collected G. cf. maximus from an unspecified locality at Siggate.

Pin Dale and Mich Low

The relations in this area differ from those in the remainder of the reef-belt in that fore-reef limestones of P1a to P1b age overlie D1 limestones of shelf facies in most places. B2 reef-limestones are present at Nunlow Quarry.

The section in Pin Dale shows D1 and D2 standard limestones passing laterally into apron-reef. Both shelf and reef facies are underlain by a tuff (see also p. 61). At Pindale Mine [SK 1629 8256] the shaft passed through Edale Shales to 90 ft and continued in tuff to 300 ft (Green and others 1887, pp. 129–30). Here the apron-reef limestones or their equivalents have been cut out by the pre-Namurian unconformity. Some original thinning of these beds may also be assumed, corresponding to the thick development of tuff beneath. The section in Pindale Quarry (loc. 47) [SK 1594 8231] shows shelf limestones of D1 and early D2 age passing northeastwards at the inner edge of the apron-reef into limestone-breccia with "angular fragments up to a foot or more in length in a matrix which is commonly seen to be markedly oolitic" (Eden and others 1964, pp. 79, 84, and (Figure 2)).

In Upper Jack Bank Quarry (loc. 142) [SK 1616 8220] 30 ft of pale massive shelly reef-limestone rest on 4 ft of grey massive limestone. The lower item is perhaps an interdigitation of standard facies in the reef. Here the reef-limestones have yielded Goniatites striatus some 2 ft from the base and also near the top of the section (Eden and others 1964, pp. 90, 102, 105); Productus productus hispidus also occurs. There is an unusually steep inward dip of up to 20° here and this is explained (ibid.) as being due to the presence of a knoll, now largely eroded away, at the edge of the reef-belt. It is here suggested that these relations could also be explained by the effects of uplift along the reef margin.

The section in Lower Jack Bank Quarry (loc. 141) [SK 1616 8234], near the foot of the frontal slope of the apron-reef, has been described in detail by Eden and others (ibid., pp. 79, 90–1) and includes their localities 9 and 11; it may be summarized as follows:

feet

Limestone (fore reef) massive, usually crinoidal and with bands of breccia; fauna of reef brachiopods including Productus productus hispidus and Orbiculoidea nitida near top (d); Goniatites sp. crenistria group in lower part (c) up to

60

Marked unconformity

(b) Limestone, grey-brown well-bedded fine-grained (shelf D1 lithofacies), with Gigantoproductus sp. maximus group

30

(a) Tuff, formerly seen in quarry floor

The uppermost apron-reef limestones were considered to lie on the same horizon as the P1b limestones of Upper Jack Bank Quarry, the presence of P. productus hispidus providing a faunal link. The lower (P1a) beds, with cf. G. crenistria were considered probably to occupy an erosional hollow in the underlying D1 limestones; elsewhere in the quarry these beds are absent, P1b limestones resting directly on D1.

In Nunlow Quarry (loc. 143) [SK 1651 8226] 0.25 mile S.E. of Pindale Farm, Eden and others (1964, p. 91) describe a sequence which is in many respects similar to that in Lower Jack Bank Quarry:

(b-c) Pale unbedded reef-limestones; these have yielded (c) Productus productus towards hispidus, near the top (?P1b); (b) Goniatiter crenistria (P1a) has been recorded from fallen material probably from the lower part (Jackson 1925, p. 272)

about 120Thicknesses added to published description.

(a) Pale massive fine-grained limestones and calcilutites, with a B2 fauna of reef brachiopods

about 40

To the south-east of the last exposure, the frontal slope of the apron-reef, clear of quarrying operations, is again visible. There appears to be a progressive south-easterly thinning of the apron. On Mich Low the apron-reef merges into a knoll-like mass forming the crest of the hill. Dips on the outer side of this cannot be observed but exposures on the inner, southern side, show dips of 37° and 25°. The underlying limestones are apparently of D1 shelf facies.

On the north-west side of Mich Low a small railway-cutting [SK 1693 8195] shows the following section of beds referred to the Bee Low Limestones:

feet

Limestone, grey massive irregular-bedded, locally oolitic; brachiopods, productoid spines and crinoid debris near base

32

Limestone, tuffaceous, and grey tuff, interbanded

0 to 3.25

Tuff, grey, soft and brown-weathering

4

The limestones of this section are referred to the back-reef facies.

The overlying reef-limestones are exposed on the south side of Mich Low (loc. 144) [SK 1699 8180] where they yield Antiquatonia cf. antiquata, Avonia davidsoni, A. sp. [juv.] youngiana group, Gigantoproductus edelburgensis, G. sp. cf. moderatus, Krotovia spinulosa, Linoproductus sp. hemisphaericus group, Pleuropugnoides pleurodon, Productus productus hispidus, Pugnax pugnus [large form]. Parkinson (1947, p. 111) has recorded Goniatites striatus from Mich Low, proving the P1b age of these beds.

To the north of Bradwell, a group of small inliers of reef-limestone is present. This appears to be an easterly continuation of the outcrops of Mich Low, the more southerly exposures dipping south towards the shelf area. An exposure (loc. 145) [SK 1740 8187] of 10 ft of poorly-bedded reef-limestone yielded a shelly fauna which is probably of low P1 age. However, on the east side of the road here (loc. 147) [SK 1749 8185] 1 ft of dark limestone contains an abundant shelly fauna of upper B2 age.

Post-reef deposits

The small outcrops of these beds, although at least in part earlier than the main mass of the Eyam Limestones (P2), have been included with them on the map.

Castleton

Beds here considered to rest on the apron-reef are present between the lower slopes of Treak Cliff and Castleton village. The Beach Beds, consisting for the greater part of rolled-shell limestones, occupy much of the outcrop. A detailed description of the lithology and fauna of the outcrops has been published by Sadler (1964) though these are differently interpreted here (see p. 35).

A section [SK 1393 8284] in a quarry by the main road shows 6.5 ft of pale, roughly bedded limestone with crinoidal bands and some broken shells. Sadler (1964, p. 368) recorded beds of basin facies beneath this: dark thinly bedded coarse-grained limestone with some brachiopods 2 ft, on dark massive coarsely crinoidal limestone with 'Zaphrentis cf. enniskilleni', 4 ft. From a nearby quarry [SK 1384 8290] 200 yd N.N.W. of the entrance to the Speedwell Mine, Jackson (1941, p. 243) records Archaeocidaris urii and the fishes Petalodus acuminatus, Strepsodus sp., Ctenopetalus lobatus and Petalorhynchus sp. (teeth).

The Beach Beds are well exposed near the Speedwell Mine. A section [SK 1385 8277] on the north side of the road shows 20 ft of rolled-shell limestone with worn shell fragments (up to 2 in diameter) and some crinoid debris; the rock is well bedded and is coarse-grained in the lowest 2.5 ft. On the south side (Plate 13B) of the Speedwell Mine [SK 1400 8270], 6 ft of rubbly rolled-shell limestone contains limestone pebbles up to 2 in. An exposure [SK 1394 8267] 50 yd S. of the Speedwell Mine shows beds near the base of the Beach Beds:

feet

(d) Limestone, pale massive irregularly bedded, finely crinoidal

4.25

(c) Limestone, grey fine-grained

1.5 to 2

(b) Limestone, dark grey thin-bedded; fmely crystalline and somewhat bituminous. Sadler (1964, p. 366) recorded Semenewia aff. concentrica (de Koninck), Dictyoclostus sp., Buxtonia sp. and Athyris sp.

1

(a) Limestone, pale massive finely crinoidal

2

The exposure is important in showing the presence of intercalations of beds of basin type in the Beach Beds.

The Beach Beds are exposed in two old quarries between the Speedwell Mine and Goosehill. The more westerly of these [SK 1423 8264] shows 20 ft of rolled-shell limestones, part crinoidal and showing rough sorting into coarser and finer bands. The more easterly [SK 1440 8261] shows rolled-shell limestone 1.25 ft on well-sorted crinoidal limestone with some shell debris 13 ft.

At a point 40 yd N.E. of the last exposure a small thickness of dark bituminous limestone, in part crinoidal, crops out. This lies at the western end of the small outcrop which extends eastwards to Goosehill. By Goosehill Hall, exposures in a lane [SK 1474 8272] show dark bituminous limestones interbedded with grey crinoidal or shelly limestone at this horizon.

On the east side of Peakshole Water another area of dark beds overlying the apron-reef is present. The beds at the base are exposed in an old quarry [SK 1488 8277], where dark shelly limestone with small crinoids 2.5 ft, overlies soft buff-coloured tuff 2.5 ft, on apron-reef (loc. 139).

A roadside exposure (loc. 148) [SK 1492 8282] in Castleton shows beds at a slightly higher horizon; dark bituminous limestone with Rotiphyllum costatum, Zaphrentites cf. derbiensis and Antiquatonia insculpta. Parkinson (1947, p. 112) noted the presence of a small exposure [SK 1586 8265] of dark limestones of probable P1b age, between Castleton and Pin Dale, yielding Goniatites cf. spirifer Roemer and resting on the upper surface of the reef. The extent of the outcrop of these beds (ibid., pl. viii) would, however, appear to have been exaggerated.

Windy Knoll and Perryfoot

This area shows remnants of dark limestone later than the apron-reef. These deposits are considered to be of P2 age on the basis of fossil evidence from near Peakshill Farm (see below).

At Windy Knoll Quarry [SK 1261 8300] deposits of the above type occur as 'Neptunian dykes' in the Bee Low Limestones.

The fillings of these are dark bituminous limestone, grey crinoidal limestone and a breccia of blocks of the country rock in a dark bituminous matrix. Parkinson (1965, p. 176) considered that these infillings were contemporaneous or nearly so with the country rock but the sharp contrast in lithology makes this unlikely.

Farther west, at the reef margin an exposure (loc. 128b) [SK 1170 8267] 130 yd E.15°

N. of Peakshill showed a few inches of dark limestone with the P2 goniatite Sudeticeras sp. resting on the upper surface of the reef-limestone and overlain by shale.

Near Perryfoot, a small outcrop of dark limestone is present, resting on beds low in the Bee Low Limestones. An exposure [SK 1062 8133] by the main road shows 4 ft of these beds.

Boreholes in the Marginal Province

Castleton Borehole

The Castleton Borehole (loc. 149) [SK 1410 8293], after passing through Namurian and Viséan shales, reached limestone at 114 ft 6 in. The section is as follows:

Thickness

Depth

feet

inches

feet

inches

Base of Namurian

99

7

Mudstone, dark, with a 7-in silty calcareous band at 101 ft 1 in; slump structures 101 ft 2 in; Caneyella membranacea (McCoy), Dunbarella aff. persimilis (Jackson), Postdonia cf. corrugata (Etheridge jun.), Lyrogoniatites georgiensis Miller and Furnish, Sudeticeras sp., conodonts (P2c)

6

11

106

6

Mudstone with thin calcareous bands and two coarser-grained thin limestones (both showing graded bedding) 0.5 in at 110 ft 1.5 in and 1 in at 110 ft 6 in; C. aff. membranacea, cf. Mesoglyphioceras granosum (Portlock), Lyrogoniatites sp., Sudeticeras ? (P2)

4

1

110

7

Mudstone, dark, with calcareous bands; 6-in band at 113 ft 8 in shows calcareous debris with graded bedding; C. aff. membranacea, Posidonia sp., Lyrogoniatites sp. at 110 ft 11 in to 111 ft 9 in (P2)

3

11

114

6

Limestone, buff-grey with dark patches, very coarsely crinoidal and shelly at top, becoming finer grained and less crinoidal below; Brachythyris cf. ovalis, Eomarginifera ?, orthotetoids, Spirifer sp. bisulcatus group, Reticularia ?

2

3

116

9

Mudstone, dark, in irregular parting about

0.25

116

9.25

Limestone-breccia of fine-grained fragments up to 2 in set in a finely crinoidal matrix; Avonia aff. davidsoni, Buxtonia sp., cf. Crurithyris sp., Fluctuaria sp. [juv], Linoproductus sp., cf. Martinothyris lineata, Productus productus, Reticularia?, Spirifer sp.

2

5.75

119

3

Limestone, grey compact, shelly in places; thin shale parting at 121 ft 9 in: Antiquatonia sp., Buxtonia sp., Linoproductus sp., P. productus, Reticularia sp., Spirifer sp. bisulcatus group

2

7.5

121

10.5

Limestone, rubbly

10.5

122

9

Mudstone, black

1

122

10

Limestone, grey-brown granular, shelly, with darker bands above 127 ft; grey-brown finely crinoidal with some shells below: Buxtonia ?, Linoproductus sp., Pleuropugnoides pleurodon, Productus productus, Reticularia sp., S. sp. bisulcatus group

5

4

128

2

Limestone, grey-brown coarsely crinoidal, with a 1-in mudstone parting at 134 ft 1 in; marked stylolite with mudstone coating at base: Antiquatonia hindi ?, Dictyoclostus?, Gigantoproductus sp., Spirifer sp.

11

1

139

3

Beach Beds

Limestone, grey-brown, crinoidal and shelly (many worn shells): some intraclasts of grey limestone: A. insculpta ?, Gigantoproductus sp., Spirifer sp.

4

0

143

3

Limestone, grey-brown, shelly (some shells worn), coarse crinoid debris in places; Dibunophyllum sp., Echinoconchus sp., Gigantoproductus spp., including G. striatosulcatus (Schwetzow) subspp., Spirifer sp.

14

3

157

6

Limestone, grey-brown coarsely crinoidal, with shells, some worn: Gigantoproductus sp., S. (F.) trigonalis

4

0

161

6

Limestone, grey coarsely crinoidal and shelly; Gigantoproductus sp., S. sp. bisulcatus group

5

6

167

0

Limestone, grey to grey-brown crinoidal, with some shells: some darker grey intraclasts; Echinoconchus cf. elegans, Linoproductus?, Spirifer sp. ; two bands with corals, one from 167 ft 3 in to 167 ft 9 in with Lithostrotion portlocki and Nemistium edmondsi; the other from 169 ft 5 in to 169 ft 7 in with Aulophyllum fungites, Dibunophyllum? and Diphyphyllum lateseptatum

5

0

172

0

Limestone, dark grey, with some worn shell debris and zaphrentoids ; Zaphrentites sp., trilobite fragment; passing into

6

172

6

Limestone, pale grey with scattered shells, some crinoid debris; bands of worn shell debris; Antiquatonia?, Eomarginifera sp., S. (F.) trigonalis, fish fragment

31

0

203

6

The borehole record confirms the association of the Beach Beds with beds of basin facies. The presence of L. portlocki with N. edmondsi at 167 ft 9 in suggests a position high in the D2 shelf succession perhaps near the P1–P2 boundary of the basin. N. edmondsi is restricted in the present area to the Upper Monsal Dale Beds and two of the three records are from or near the horizon of the L. duplicata Band. It is uncertain whether the limestones above 139 ft 3 in have been included at outcrop with the Beach Beds or whether they thin out and disappear in that direction.

Hope Cement Works Borehole

The Hope Cement Works Borehole (loc. 150) at Salter Barn approximate position [SK 1678 8228]Now covered by Earle's Cement Works. was described by Feamsides and Templeman (1932, pp. 105–10). Templeman's unpublished record may be summarized:

Thickness

Depth

feet

feet

Base of Namurian (see p. 200)

280

Mudstone, dark, with calcareous bands; Posidonia corrugata at 285 ft, indeterminate goniatites throughout; fish and plant debris 282 ft 6 in to 287 ft

12

292

Mudstone, dark platy with phosphate and pyrite nodules; some fish scales

5

297

Limestone, dark; indeterminate goniatites

1

298

Limestone, of very varied lithology, including grey to dark grey thin-bedded limestones with shale partings, limestone breccias and tuffaceous beds; coarsely bioclastic bands are Shelly or crinoidal; Lonsdaleia duplicata duplicata 299 to 309 ft; Productus productus at 306 ft; 8 in of dark limestone with Amplexizaphrentis?, Claviphyllum eruca (McCoy) and Rhopalolasma sp. at 310 ft 8 in; Weberides sp. at 342 ft

52

350

Tuff

1

351

Lava, predominantly with pillow structure; some thin

tuff bands and sporadic thin partings of limestone

101.5

452.5

Tuff

3

455.5

Limestone, tuffaceous

15

470.5

Tuff

19.5

490

Lava, poor pillow structure

9.5

499.5

The lavas are all recorded as vesicular. The figure by Fearnsides and Templeman (ibid., p. 108) of a length of core from 378 to 383 ft shows an arrangement of vesicles becoming finer towards the outside of each pillow. As these authors remark, the succession in the borehole cannot be correlated in detail with the known sequence. Eden and others (1964, p. 76) suggested that the igneous rocks lay on the horizon of the Pindale Tuff. This correlation does not hold as (a) the volcanic rocks of the borehole are overlain by limestone bearing L. duplicata duplicata and their tuffaceous partings show them to be closely associated, (b) beds of P1 age are present on the apron-reef front near this locality and there is no reason to suppose a sudden flattening of the outward dip, (c) there is no evidence of lava at this horizon under the quarry area. The igneous rocks are here interpreted as of later P1 (upper D2) or P2 age and lying near an unexposed eruptive centre.

Basin Province

Edale Borehole

The succession in the Edale Borehole [SK 1078 8493] at Barber Booth, was described by Hudson and Cotton (1945b, pp. 1–36). Viséan beds were passed through between 325 ft and the bottom of the hole at 757 ft. The following description is based on that of Hudson and Cotton with minor revision of fossil names:

Thickness

Depth

feet

feet

Base of Namurian (see p. 186)

325

Beds of P2 age

Shales with thin argillaceous limestones; black pyritous limestone, part crinoidal, more abundant crinoid debris 348 to 357 ft; Neoglyphioceras subcirculare (Miller) and Sudeticeras cf. stolbergi at 330 to 336 ft; N. subcirculare at 344 to 348 ft. Other fossils include Zaphrentites cf. oystermouthensis (Vaughan), Chonetes laguessianus de Koninck, Martinia aff. glabra, Caneyella membranacea, cf. Posidonia corrugata

47

372

Limestone, cherty, grey crystalline shelly to 377 ft; bioelastic with limestone and tuff fragments, with Hyalostelia smithii Young and Young, to 382 ft; alternating pale bioclastic and dark limestone with foraminifera and algae including 'Girvanella' to 410 ft; dark fine-grained limestone to 419 ft. Other fossils include Zaphrentites cf. disjunctus (Carruthers), Eomarginifera setosa, Product us concinnus J. Sowerby and Krotovia  spinulosa

47

419

Beds of upper P1 age

"Lower Shales-with-limestones"; black crinoidal limestone with paler limestone pebbles and some chert pebbles to 420 ft; tuff, re-worked with "granular carbonates" to 422 ft; shales with bunions and a few argillaceous limestones with Posidonia becheri Bronn [abundant], Eomarginifera tissingtonensis, Goniatites elegans Bisat (at 441 to 445 ft) to 445 ft; limestone, black crinoidal and shelly to 449 ft; mudstone, pyritous with black crinoidal limestones to 458 ft; shale with some grey crinoidal limestone and fragments of black mudstone to 464 ft; calcareous mudstone with bullion, argillaceous limestones and some shelly limestones with P. becheri [common], G. falcatus Roemer (490–493 ft); other fossils include Plicochonetes waldschmidti Paeckelmann and G. striatus group to 493 ft

74

493

"Pebbly and crinoidal shell limestones"; coarsely bioelastic shelly and crinoidal limestones, dark except from 500 to 505 ft; 5 ft shale and black limestone with G. striatus group at 500 ft; 2 ft shale with some black limestone at 507 ft; fauna includes Linoproductus hemisphaericus, Antiquatonia insculpta, A. sulcata and Echinoconchus elegans

19

512

Beds of lower P1 age

Calcareous mudstone with crinoid debris

4

516

Limestone, grey coarsely crinoidal and shelly limestone with some calcareous mudstone

526

Fragmental shelly limestone, slightly tuffaceous, with some blue and black chert

4

530

"Upper tuff and tuffaceous limestones", interbedded, the tuffs pyritous in places and grey or green in colour, the limestones shelly, crinoidal and tuffaceous

30

560

Limestone, dark tuffaceous, cherty and crinoidal to 570 ft; shelly with mudstone partings with Nomismoceras and Prolecanites to 578 ft; black mudstone with G. crenistria (s.l.) to 580 ft; dark argillaceous cherty and tuffaceous to 585 ft; pale grey shelly and tuffaceous to base

28

588

Tuff and tuffaceous limestone

6

594

Limestones, dark grey, some crinoid and shell debris, chert, thin shale partings; 2 ft pebbly at 599 ft and 3 ft pebbly at 609 ft; 2 ft with 'nodules enclosing shell fragments' (probably algal) at 611 ft; argillaceous limestone and shale with occasional volcanic fragments 611–614 ft; shale with a little bedded tuff to 617 ft

23

617

[In addition to the fossils listed above, the beds from 512 to 617 ft yielded a fauna including Nomismoceras cf. spirorbis (Phillips), Antiquatonia antiquata, A. sulcata, Echinoconchus punctatus, Linoproductus hemisphaericas, Pustula pustulosa (Phillips), Striatifera striata.]

Beds of D1 and D2 ageOnly that part of the post-D, beds with a coral-brachiopod fauna (i.e. D2 pars) is included here, the higher beds with a goniatite fauna being represented by their P1–P2 equivalents.

Limestone, pale grey foraminiferal, slightly crinoidal in places with bands of limestone breccia; tuff pebbles between 632 and 637 ft

43

660

Limestone, dark grey often shelly or crinoidal, with shale partings in upper part; some pebbly bands; 3 ft dolomitic at 665 ft; 3 ft with tuff fragments at 670 ft; fossiliferous throughout, especially 660 to 662 ft ; fossils include 'Girvanella' (especially 670 to 680 ft), Palaeosmilia murchisoni, Echinoconchus punctatus, Gigantoproductus maximus, Plicatifera plicatilis, Sinuatella sinuata

29

689

'Calcite-mudstones', some brecciated

23

712

Limestone, dark grey to dark brown ; finely crystalline and dolomitic to 730 ft; finely fragmented and ?dolomitic below

45

757

[The beds between 689 ft and 757 ft yield a poor fauna composed mainly of productoids].

Fossils from this borehole are not included in the appendices. The stratigraphy of the borehole is discussed on p. 36.

Alport Borehole

The Alport Borehole [SK 1360 9105] near the junction of Swint Clough and the River Alport was also described by Hudson and Cotton (1945a, pp. 254–311). The following description is abridged from their account, though the fossil names have been brought up to date and certain of the goniatite determinations and zonal boundaries revised.

Thickness

Depth

feet

feet

Base of Namurian (see pp. 195–7)

1099

Lyrogoniatites georgiensis (P2c) Zone

Mudstone, calcareous with nodular and calcareous bands; Caneyella membranacea, Dimorphoceras sp., Girtyoceras costatum (Ruprecht), G. shorrocksi Moore, G. cf. waitei Moore, Lyrogoniatites georgiensis Miller and Furnish

8

1107

Neoglyphioceras subcirculare (P2b) Zone Mudstone, with a few thin beds of limestone ; Caneyella membranacea, Dimorphoceras sp., Sudeticeras stolbergi

12

1119

Mudstone, calcareous with sporadic thin limestones; 2 ft bed with phosphatic nodules at 1123 ft; Paraconularia sp., Rugosochonetes sp., Caneyella membranacea, Dunbarella sp., Dimorphoceras sp., Neoglyphioceras subcirculare at 1124 to 1126 ft; Sudeticeras spp.(including S. splendens Bisat sp.) at 1135 ft

19

1138

Mesoglyphioceras granosum (P2a) Zone

Mudstone, dark grey calcareous, with some thin-bedded limestone; Asterocalamites scrobiculatus (Schlotheim), Paraconularia sp., Caneyella membranacea, Dunbarella sp., Kazakhoceras cf. hawkinsi (Moore), Mesoglyphioceras granosum, Sudeticeras sp.

12

1150

Mudstone, dark grey calcareous, with a thin band of hard grey limestone in lowest 3 ft; Paraconularia sp., C. membranacea, Dunbarella sp., orthocones, Monograptus granosum, Neoglyphioceras sp.

12

1162

Mudstone, dark grey calcareous, with hard grey bioclastic and fragmental limestones; a little chert below 1172 ft; Hyalostelia sp., Lingula sp., productoid spines, Aviculopecten sp., C. membranacea, Dunbarella sp.

24

1186

Limestone, with limestone pebbles and breccia and some mudstone fragments; some intraclasts of ? decomposed tuff; Antiquatonia sp., Sudeticeras sp.

10

1196

Goniatites koboldi (P1d) Zone

Mudstone, lowest 5 ft with bands of brownish and grey limestone; Antiquatonia sp., Chonetes sp. [s.l.,] Gigantoproductus sp., Epistroboceras sulcatum (J. de C. Sowerby), orthocones, goniatites indet.

11

1207

Mudstone, dark grey calcareous, with bands of very fine-grained grey limestone in beds up to 1 ft; ?Posidonia becheri, nautiloids, Dimorphoceras sp., G. koboldi Ruprecht group, Sudeticeras sp.

23

1230

Goniatites sphaericostriatus (P1c) Zone

Mudstone, grey and greenish grey, also fine-grained grey limestones, some chert and brownish grey limestone; cf. Sphenopteridium dissectum (Goeppert), Sphenoptenis foliata Stur, echinoid plates, P. becheri (abundant at 1233 and 1285 ft), Goniatites bisati Moore, G. kajlovecensis Patteisky, G. cf. waldeckensis Haubold, G. sphaericostriatus Bisat, Neoglyphioceras spirale(Phillips) (at 1274 ft)

55

1285

Mudstone, with some limestone bands; P. becheri, G. elegans Bisat, G. aff. falcatus, striatoid goniatites indet.

17

1302

Goniatites falcatus (P1b) Zone

Mudstone with limestone bands, some coarse shelly and crinoidal, more abundant than in higher beds, some chert; foraminifera, Rugosochonetes sp., productoids including Overtonia fimbriata; P. becheri, G. falcatus, G. spirifer

35

1337

Goniatites crenistria (P1a) Zone

Limestone, part dark grey argillaceous and fragmental, foraminiferal, and part brownish dolomite-mudstone

7

1344

Limestone, mainly grey fine-grained, with some brachiopod fragments, some mudstone; Hyalostelia sp., P. becheri, Nomismoceras vittiger (Phillips), G. crenistria, G. cf. concentricus Hodson and Moore

32

1376

Limestone, grey and grey-brown, with mudstone at top and dark grey mudstone with crinoid debris and pebbles of limestone and tuff; beds of tuffaceous limestone with pyrite at 1378 and 1384 ft.

8

1384

Mudstone, with fine-grained grey limestone in beds up to 2 ft thick, sporadically crinoidal and sometimes shelly; some of the limestones pyritous, rarely cherty; mainly limestone 1409 to 1416 ft, tuffaceous debris at 1408 and 1415 ft, and in thin bands at 1426 and 1433 ft; 2 ft dark grey argillaceous limestone with pebbles of limestone and tuff at 1421 ft; Dunbarella sp., P. becheri, Rineceras sp., Epistroboceras sulcatum, and G. crenistria group

50

1434

Limestone, pale grey coarsely bioclastic with worn shell and crinoid debris to 1436 ft; dark grey fine-grained with lapilli of greenish tuff to 1437 ft; black argillaceous with crinoid and shell debris, some in pyrite, and greenish tuff 'lapilli' to 1438 ft; grey-brown fine-grained to 1440 ft; dark argillaceous with crinoids, brachiopods, tuff 'lapilli' and limestone pebbles, thin layers of laminated tuffaceous mudstone near base to 1445 ft

11

1445

Tuff and tuffaceous mudstone, banded, often pyritous, with banded and nodular chert; some slump structures

15

1460

Limestone, platy and slightly tuffaceous

8

1468

Tuff, bluish grey calcareous with thin tuffaceous mudstone at base, banded and nodular chert

7

1475

Limestone, argillaceous and mudstone, with chert; bryozoa, G. crenistria group at 1478 ft

15

1490

Upper Beyrichoceras (B2) Zone

Mudstone and brownish grey or dark grey argillaceous limestone, shelly and crinoidal in parts, thin bands of tuff at 1493, 1508, 1512, 1536 and 1537 ft; Dunbarella sp., Beyrichoceras aff. delicatum, Bollandoceras micronotum, G. crenistria group, G. aff. hudsoni, G. struppus, Nomismoceras?

52

1542

Limestone, brownish grey or grey; cf. Actinoconchus sp., Chonetes sp. (s.l.), Pustula sp., Beyrichoceras cf. delicatum, Prolecanites discoides, Pronorites cyclolobus (Phillips), ostracods and a trilobite fragment

68

1610

Limestone, dark brownish grey, with shale, tuffaceous and with slumping below 1632 ft; Lingula sp., Dunbarella sp., Bollandites cf. phillipsi (Bisat), G. maximus group possibly G. maximus var. b Bisat, Prolecanites cf. discoides

32

1642

Limestone, brownish grey, argillaceous in places, with some thin calcareous mudstone bands; some chert from 1651 to 1664 ft; athyroid, spiriferoids, cf. Paralielodon tenuistriatus (McCoy), orthocone nautiloid, Goniatites sp. ?maximus group, Nomismoceras sp.

59

1701

Lower part of Lower Dibunophyllum (D1) Zone

Limestone grey or brownish grey fine-grained; calcilutite and chert nodules in places; nodular pebble bed at 1781 ft and crinoidal limestones with productoids and corals at 1853 ft; from 1701 to 1780 ft fossils as follows: bryozoa, Antiquatonia ?, athyroid, Chonetes hemisphaericus von Semenow, Chonetipustula earringtoniana (Davidson), Composita cf. ambigua (J. Sowerby), Krotovia spinulosa, Plicochonetes aff. elegans (de Koninck), P. aff. ventricosus (Tomquist), Rhipidomella?, spiriferoids, Ptychomphalus sp. ; 1781 ft, Chaetetes sp., Michelinia sp., Avonia sp., Chonetipustula carringtoniana, Plicochonetes sp., spiriferoid, ostracods; from 1781 to 1850 ft, Antiquatonia ?, P. aff. elegans, ?Coelonautilus konincki (d'Orbigny); from 1850 to 1852 ft, Caninia amplexoides (Wilmore), Cladochonus sp., L. pauciradiale, Syringopora ?, Chonetipustula sp., chonetoid, orthotetoid, Rhipidomella?, Paraparchites sp. ; from 1852 to 2027 ft, cf. Permia, C. cf. carringtoniana, Lingula parallela McCoy, Megachonetes cf. dalmanianus (de Koninck), Orbiculoidea cf. tornacensis Demanet, orthotetoid, P. aff. elegans, Tornquistia aff. polita (McCoy), orthocone nautiloid

326

2027

Seminula (S2) Zone

Limestone, dark brownish grey dolomitic unfossiliferous, some calcilutites, chert quite common, some mudstone partings, rare beds with shell debris; 1-ft bed at 2028 ft with crinoid and shell debris and (algal) pellets; foraminifera, Cryptophyllum ?, Cyathaxonia rushiana Vaughan, Lithostrotion sociale, Rotiphyllum sp., Rylstonia sp., cf. R. benecompacta Hudson and Platt [juv.], Zaphrentites sp. cf. Z. lawstonensis (Carruthers), chonetoids, Cornposita ?, Linoproductus corrugatohemisphericus, Overtonia fimbriata, Reticularia sp., Bollandoceras?

109

2136

Limestone, dark brownish grey, dolomitic cementstones with calcareous mudstone partings and chert; bands of calcilutite, some with pyrite; 1.5 in of tuffaceous mudstone and limestone at 2300 ft, calcareous shale predominant and chert rare in top 143 ft; calcilutites and dolomite-mudstones more abundant in bottom 83 ft; Cyathaxonia rushiana, Rotiphyllum sp., bryozoa, Antiquatonia ?, Chonetipustula carringtoniarta, C. cf. plicata (Sarres), ?Cleiothyridina royssii (Davidson), Lingula elliptica Phillips, Linoproductus corrugatohemisphericus [juv.], 0. fimbriata, Phricodothyris sp., Pustula sp., Semenewia sp., Aviculopecten sp.,'Pseudamussium' sp., Phillibole cf. megalophthalma (Weber), P. cf. polleni (H. Woodward), ostracods

226

2362

Limestone, dark grey fine-grained dolomitic, with shell and crinoid fragments, some chert and ?'lapilli' of light grey tuff

4

2366

Limestone, grey medium-grained, "conglomeratic", with shell and crinoid debris; pebbles of shale, pellet limestone and dark grey fine-grained limestone; many fragments, 'lapilli' or pebbles of blue and green tuff (up to 3 in diameter); abundant corals including Caninia cf. amplexoides, Cyathaxonia rushiana, Diphyphyllum smithi Hill, Fasciculophyllum cf. densum (Carruthers) [juv.], Lithostrotion martini, L. minus (McCoy), Rotiphyllum sp., Rylstonia dentata Hudson and Platt subsp., chonetoid, Davidsortina carbonaria

5

2371

Limestone, dark grey grained argillaceous, some calcilutites and shale; Cyathaxonia rushiana, F. den-sum, Rotiphyllum sp., Chonetipustula sp., D. carbonaria, Linoproductus sp.

20

.

2391

Breccia ( ?contemporaneous), of limestone and calcareous mudstone, passing down into mudstone with thin limestone bands, "both crumpled"

1

2392

Limestone, dolomitic, resting with high angle junction on fine-grained dolomitic limestone with pebbles of porcellanous limestone, recrystallised tuffaceous mudstone, pellet limestone, tuff and some chert. Fossils rare; F. densum, Leiorhynchus sp., productoids, Platyceras ?

4

2396

Limestone, dark grey argillaceous and dolomitic, with chert and rare shell and crinoid debris

7

2403

Limestone, fine- and coarse-grained dolomitic, with oblique mudstone partings (dip 60° to 70°), crinoid debris and limestone pebbles; Cyathaxonia rushiana, F. densum, L. cf. martini

3

2406

Limestone, dolomitic and crinoidal with chert, limestone conglomerate with mudstone parting (dip 70°) in middle; Cyathaxonia sp., Rotiphyllum sp., Zaphrentiles cf. ashfellensis (Lewis),

D. carbonaria, Phricodothyris sp., productoids, rhynchonelloid

2

2408

Limestone, dark grey fine-grained, subangular limestone pebbles in lower 2 ft; chert and crinoid debris; Z. enniskilleni, Lingula parallela

4

2412

Limestone breccia, dark grey, with limestone and some tuff fragments (up to 4 in by 4 in); veined with calcite, baryte, sphalerite and fluorite; L. cf. martini, Rotiphyllum sp., Rylstonia aff. dentata, Eomarginifera derbiensis, Pustula sp. [juv.], Rhipidomella michelini

5

2417

Limestone, dark grey fine-grained, dolomitic slightly crinoidal, with some black chert; Aulina sp., Cyathaxonia rushiana, F. densum [juv.], Michelinia sp., Lithostrotion sp., Rhopalolasma sp. cf. R. syrnpecta Hudson, Rotiphyllum nodosum Smyth, R. aff. rushianum Smyth non Vaughan, Antiquatonia ?, Avonia sp., Chonetipustula cf. plicata, Echinoconchus eximius, Krotovia sp., Linoproductus sp., Plicochonetes sp., cf. Productina transversistriatus (Paeckelmann), rhynchonelloid, Psephodus sp.

14

2431

Limestone, dark grey fine-grained, dolomitic in upper part, thin mudstone partings throughout; rare chert; Z. enniskilleni, L. corrugatohemisphericus

124

2555

Hudson and Cotton (ibid., p. 256) named the shales above 1302 ft the "Alport Shales" and these were underlain by the "Alport Limestones-with-Shales" extending to 1642 ft and the "Alport Limestones" to the base of the hole at 2555 ft. The term "Alport Shales" is here discontinued as the uppermost 45 ft (originally 26 ft) falls within the Namurian and the remaining terms are of local value only. The stratigraphy of the borehole is discussed on pp. 36–7 and it should be noted that fossils from the borehole have not been included in the lists in the appendices. I.P.S.

Petrography of the igneous rocks

Lavas

Most of the following descriptions apply to the Lower Miller's Dale Lava from which it has been possible to obtain reasonably fresh specimens. The less extensive outcrops of the Upper Lava have yielded satisfactory materials for slicing at one locality only.

Lower Miller's Dale Lava

In all the specimens examined, the Lower Lava consists of olivine-basalt or basalt, of dark grey to grey-green colour, mottled black or red-brown (where hematitized) and containing sporadic pseudomorphous phenocrysts or glomeroporphyritic aggregates mainly 1 to 3 mm across. Vesicles or sub-vesicular patches are generally conspicuous, being filled with white carbonates and/or dark chlorite. The groundmass is generally fine-grained though crystals are usually visible macroscopically. Specimens from outcrop as well as from bore-holes are invariably highly altered through chloritization, carbonation and hematitization, which have affected in particular primary ferromagnesian minerals. The feldspars, however, are least altered, and form in the groundmass a mesh of laths which are generally randomly arranged, though in places (particularly around vesicles and phenocrysts) they show fluxioning. Labradorite predominates in both groundmass and phenocrysts. In the least altered specimens, the essential ferromagnesian mineral is pale green clinopyroxene near augite in composition. Pseudomorphs after olivine are generally present. Opaque ores include ilmenite and magnetite. Evidence for the occurrence of composite lava flows is presented below.

I.C.I. Borehole T/B/23A Great Rocks Dale [SK 0985 7614] (see p. 52)

(1) 30 to 63.5 ft: This consists predominantly of grey-green (speckled black) coarse-grained olivine-basalt (groundmass granularity averaging 0.6 by 0.1 mm), with calcite veining at 35 to 36 ft, and sporadic hematitization at 30 to 31 ft, 34 to 35 ft, 42 to 45 ft. The groundmass becomes a little finer grained with depth. A strongly pleochroic, fibrous clay mineral occurring in veinlets at 45 ft (with X = blue-green, Z = green; absorption X > Z), was identified by an X-ray powder photograph (NEX 801)NEX numbers refer to the X-ray powder photograph collection of the North of England Office of the Institute of Geological Sciences; E numbers refer to the Sliced Rock Collection of the Institute. as a chlorite. A section (E35229) 1 from 35 ft 8 in consists of pseudomorphous olivine phenocrysts, up to 3 mm in length, in glomeroporphyritic aggregates, and a groundmass mesh of randomly orientated labradorite laths (near Ab46An54) averaging 0.6 by 0.1 mm, which show some fluxioning around the phenocrysts. Accessory ilmenite forms randomly arranged laths, transgressing feldspars. Ferromagnesian minerals have been completely replaced by chlorite and carbonate. Feldspar laths show central alteration to a pinkish clay mineral, carbonate and leucoxene. Interstitial minerals include microgrowths of potash feldspar, apatite needles, xenomorphic quartz, chlorite and calcite. Chlorite is mainly olive-green, vermiform and radially fibrous, patchily stained by hematite. Subvesicles have chloritic rims and calcite cores. A further specimen (E35230) of olivine-basalt at 45 ft 10 in is considerably less altered. The groundmass framework of labradorite (near Ab43An57) laths includes colourless to pale green, granular, allotriomorphic to hypidiomorphic fresh augite (averaging 0.08 mm across). Phenocrysts range up to 1.5 mm in length, are composed of carbonate, chlorites and chalcedony, and are pseudomorphous after probable olivine. Intergranular constituents include brown and green chlorites, chalcedony, quartz and rather sparse carbonate. There are plentiful laths of strongly transgressive accessory ilmenite. Specific gravities of three specimens at 36 ft 3 in, 38 ft 5 in and 45 ft 10 in were determined as 2.55, 2.54 and 2.63, respectively.

(2) 63.5 to 79 ft: A lithological change occurs at 63.5 ft, for the basalt is both finer grained, darker coloured and considerably more stained by hematite from this depth to 78 ft. Veining by calcite and vesicular development are also more pronounced (65 to 68 ft and 76 to 79 ft) than in the higher core described above. As a result of the hematitization, specific gravities are also a little higher-2.79 and 2.76 for specimens at 76 ft 2 in and 77 ft 1 in respectively. A sectioned core at 66 ft (E35231), (E35232) is fine-grained, chloritized, hematitized and carbonated olivine-basalt, with pseudomorphous phenocrysts after probable olivine attaining 1.0 by 0.5 mm, scattered in a highly altered mesh of albitized plagioclase laths (averaging 0–4 by 0.08 mm), which are locally fluxioned around phenocrysts or subvesicles. Primary ferromagnesian minerals have been completely replaced. There are plentiful laths of partly leucoxenized ilmenite, with intergranular chlorite and carbonates. Olivine pseudomorphs are composed of patchy olive-green chlorite with hematitic veining. Vesicles (1 to 2 mm diameter) are filled with coarse calcite, green chlorite and chalcedony, fringed with opaque oxides and fluxional plagioclase laths. A stringer of the pleochroic clay mineral described above (at 45 ft) also occurs in this section. The fibres are arranged normal to the stringer walls. A section (E35233) at 77 ft 4 in is closely similar.

The evidence that the two basalts described represent individual flows is supported by their distinct lithologies, and in particular by the intensive hematitization of the lower basalt which may indicate subaerial weathering prior to the later flow and development of vesicles.

Sink-hole, north of Water Swallows [SK 0836 7557]

A specimen (E32820) of the lava (see p. 52) is a green-grey (patchily stained purple) amygdaloidal olivine-basalt. It is somewhat coarse-grained with plagioclase laths forming the groundmass framework, averaging 0.6 by 0.1 mm, phenocrysts attaining 1.5 nun across. Glomeroporphyritic aggregates attain 3 mm across and other phenocrysts appear to represent pseudomorphous olivine crystals, replaced by carbonate and chlorite and veined by opaque oxides. Other coarse structures formed of iron oxide, chlorite and quartz are too irregular for identification, but may also represent replaced olivine crystals. Feldspars retain albite twinning but have been albitized and largely replaced by chlorite. There is abundant interstitial material (mainly olive-green chlorite, quartz and carbonate) and individual grains of chlorite may represent pseudomorphous pyroxene. There are plentiful opaque ilmenite laths and irregular hematite. Vesicles are commonly filled with calcite rimmed by chlorite and contain patches of chalcedony.

Cave Dale, Castleton [SK 1478 8218]

Though the hand specimen (E33466) is apparently fresh, dark green-grey, fine- to medium-grained, and charged with vesicles, in section the basalt is heavily carbonated and chloritized. The feldspar laths forming the rock framework (averaging 0.07 by 0.4 mm) are largely replaced by carbonate and chlorite. There is a brown mesostasis which includes leucoxene, chlorite and some potash feldspar. Accessory laths and needles of partially leucoxenized ilmenite are common Vesicles average 1 mm diameter and contain radially fibrous chlorite in outer zones, with scalloped fringes lined with chalcedony and carbonate cores.

Upper Miller's Dale Lava

Roadside exposure, Bole Hill [SK 1059 7545]

A specimen (E32828) of relatively fresh olivine-basalt from this exposure is dense, dark grey and aphyric, with abundant, black, irregular micro-amygdaloidal patches up to 3 mm across. In section there are sparse chlorite pseudo-morphs after olivine (up to 0.4 mm across) scattered in a mesh of fresh plagioclase laths, averaging 0.4 by 0.06 mm, later undulose plagioclase and inter-granular allotriomorphic colourless to pale pink augite (0.1 to 0.2 mm across). The principal plagioclase is labradorite near Ab42An58. There are plentiful laths of opaque ore, principally magnetite. The fine-grained interstitial matrix is composed principally of chlorite, which commonly exhibits vermiform brownish zones set in a pale green, radial-fibrous base containing microglobules of chalcedony. Carbonate patchily replaces labradorite laths.

Cressbrook Dale Lava

Tansley Dale [SK 1728 7521]

A specimen (E33474) is dark green-grey, vesicular, olivine-basalt, with amygdales showing preferred orientation and interconnection by strings of calcite and hematite. The basalt consists of likely phenocrysts after olivine (0.6 mm) and a plexus of fine (0.2 by 0.05 mm) albitized, plagioclase laths heavily replaced by chlorite, quartz and carbonate. Intra-feldspar matrix is occupied by olive-green chlorite, carbonate, hematite, quartz and opaque granules (pyrite, leucoxene, ilmenite-magnetite). There are plentiful laths of ilmenite which show some fluxioning. Primary ferromagnesian minerals may be represented by intrafeldspar chloritic grains and subhedra. Vesicles are common, ranging up to 4 mm diameter and are filled with microglobular green chlorite, fringed with darker chlorite, hematite or carbonate, and set in a coarse calcite cement.

A second specimen (E33474A) is less vesicular and less altered, with glomeroporphyritic aggregates of carbonate and quartz, representing olivine phenocrysts (1 to 2 mm). Plagioclase laths (0.6 by 0.1 mm) are fluxioned in places and are composed of labradorite, near Ab42An58. Primary ferromagnesian minerals, however, have been completely altered to chlorite which, together with ilmenite and leucoxene, form much of the intra-feldspar matrix.

Wardlow Mires No. 1 Borehole [SK 1850 7553] (see p. 93)

The lava is a dark green-grey basalt speckled with black chloritic patches. In places feldspar laths form microphenocrysts, and vesicles are prominent, especially towards the top of the flow, where they are filled with calcite and chlorite. Towards the base of the lava, there is a brecciated structure, with rounded masses of purple-grey basalt, marginally altered to green chlorite, engulfed in a complex of layered or irregular pumiceous fragments and cemented by dark basalt and chlorite. This coarse structure may, perhaps, represent a flow-breccia, though this interpretation awaits a complete description of the core. The high proportion of chlorite cement might perhaps suggest a degree of partial magmatic refusion of solidified and brecciated lava blocks prior to incorporation in the lava flow. The sharp contacts between pyroclastic (or pseudopyroclastic components) and chlorite cement, however, do not indicate that severe chemical or physico-chemical reaction between them has in fact occurred, and the injection of the chlorite cement took place within solidified and relatively non-reactive fragments.

A specimen (E35260) of the least vesicular lava is dark grey, aphyric, speckled black with a streaky segregation of coarser chlorite. In section, the basalt is highly altered and consists of a mesh of albitized plagioclase laths (averaging 0.9 by 0.09 mm), skeletal opaque ores (partly leucoxenized), and much interstitial, olive-green, vermicular chlorite, some representing replaced primary ferromagnesian minerals, and a little carbonate.

Pyroclastic rocks

Dove Holes Tuff

Holderness Quarry [SK 0833 7821] (see p. 54)

The material (E33477A) is an aggregate of calcite particles, with interstitial green chlorite particles, flakes and galls, charged with fine pyrite crystals. Two rounded limestone lapilli (E33905), (E33906) contain chlorite and pyrite particles, have vesicular chloritic skins, and show a degree of recrystallization.

Litton Tuff

Temporary section, Litton [SK 1676 7517] (see p. 75)

A volcanic bomb measures 12 cm by 8.5 cm maximum thickness and 11 cm maximum width, tapering with curved surfaces to a characteristic 'tail'. It consists of very vesicular purple-grey basalt, the vesicles being sparse on outer surfaces and showing little elongation on broken surfaces, where they are filled with white calcite. A thin section (E33489) taken near the thickest part of the bomb, shows a mesh of feldspar lath swarms (laths averaging 0.1 by 0.02 nun) fluxioned around abundant vesicles (1 to 2 mm diameter) and pseudomorphous phenocrysts. The groundmass feldspar is principally labradorite near Ab46An54 The pseudomorphs (up to 1.5 mm length) appear to be after feldspar, and possibly olivine. The intra-feldspar matrix consists of chlorite, hematite, opaque dust (mainly leucoxene) and quartz. Vesicles are spheroidal to highly irregular, vary in size, and are filled with calcite, chlorite, fibrous chalcedony and a likely zeolite, probably analcime.

The tuffaceous matrix is highly weathered and consists of abundant lapilli, principally of pumice, set in a matrix of pumice, chlorite and leucoxene. Vesicles are filled with chlorite and chalcedony.

Wardlow Mires No. 1 Borehole [SK 1850 7553]; 613 ft 3.5 in to 614 ft 6 in

The Litton Tuff (E35756), (E35757), (E35758), (E35759), (E35760), (E35761), (E35762) consists of a large number of thin graded siltstones–silty mudstones, with intercalated, cross-bedded, coarser sandy units, structureless mudstone bands, seams of calcite and pyrite, with richly fossiliferous microcoquinoidal limestone at the base and top of the tuff ((Plate 22), fig. 2). Fluorite also occurs near the top. In the microcoquina there is a small proportion of tuffaceous particles indicating slight contemporaneous volcanic activity, and certain organic shells appear to have been replaced, prior to burial, by chlorite. The graded tuffaceous siltstone units (6 to 20 mm thick) each consist of pale grey calcitic silt grading upwards into dark grey calcareous mudstone, with variable amounts of pyrite. Pale red-brown, pyroclastic particles (pumice and shards up to 0.08 mm) are plentiful in the coarser basal layers of the graded units, and consist of a radial-fibrous mixed-layer clay mineral (X-ray powder photographs NEX 815–7). Some shards have been replaced by calcite. Finer topmost parts of the units are turbid with orientated clay minerals, carbonate, fine shards, leucoxene and scattered pyrite. The succession indicates periodical accumulations of fine pyroclastic particles concurrently deposited with calcarenite and chemically precipitated carbonate. In some units, the pyroclastic particles have been replaced by calcite. R.K.H.

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SHIRLEY, J. and HORSFIELD, E. L. 1940. The Carboniferous Limestone of the Castleton–Bradwell area, North Derbyshire. Q. Jl geol. Soc. Lond., 96, 271–99.

SHIRLEY, J. 1945. The structure and ore deposits of the Carboniferous Limestone of the Eyam District, Derbyshire. Q. Jl geol. Soc. Lond., 100, 289–310.

SIBLY, T. F. 1908. The faunal succession in the Carboniferous Limestone (Upper Avonian) of the Midland area (North Derbyshire and North Staffordshire). Q. Jl geol. Soc. Lond., 64, 34–82.

SMITH, E. G., RHYS, G. H. and EDEN, R. A. 1967. Geology of the country around Chesterfield, Matlock and Mansfield. Mem. geol. Surv. Gt Br.

SMITH, S. and YO, C. C. 1943. A revision of the coral genus Aulina Smith and descriptions of new species from Britain and China. Q.Jl geol. Soc. Lond., 99, 37–62.

STOCKDALE, P. B. 1922. Stylolites: their nature and origin. Indiana Univ. Stud., 9 (55), 1–97.

TIDDEMAN, R. H. 1889. On Concurrent Faulting and Deposit in Carboniferous Times in Craven, Yorkshire, with a Note on Carboniferous Reefs. Rep. Br. Ass. Advmt Sci., 600–3.

TRAILL, J. G. 1939. The geology and development of Mill Close Mine, Derbyshire. Econ. Geol., 34, 851–89.

VAUGHAN, A. 1905. The palaeontological sequence in the Carboniferous Limestone of the Bristol area. Q. Jl geol. Soc. Lond., 61, 181–307.

WATSON, W. 1811. A delineation of the strata of Derbyshire. Sheffield.

WELLER, J. Monograptus 1960. Stratigraphic principles and practice. New York.

WHITEHURST, J. 1778. An inquiry into the original state and formation of the earth. London.

WOLFENDEN, E. B. 1958. Paleoecology of the Carboniferous reef complex and shelf limestones in north-west Derbyshire, England. Bull. geol. Soc. Am., 69, 871–98.

WOLFENDEN, E. B. 1959. New sponges from Lower Carboniferous reefs of Derbyshire and Yorkshire, England. J. Paleont., 33, 566–8.

Chapter 3 Stratigraphical palaeontology of the Carboniferous Limestone Series

Introduction

The most important feature of the Carboniferous Limestone Series of the district is the development of reef-limestones at the northern edge of the outcrop, and from the time of Martin, J. and J. de C. Sowerby and McCoy, more than one hundred years ago, the area has been famous for its well-preserved fossils. Sibly (1908) was the first to apply Vaughan's (1905) coral-brachiopod zonal scheme to the Derbyshire limestones. It was only following Bisat's researches into Carboniferous goniatites (1924; 1934), however, that the importance of the apron-reef stratigraphy and its bearing on the correlation of the coral-brachiopod zones of the shelf facies with the goniatite zones of the basin facies was fully appreciated. Shirley and Horsfield (1940), Parkinson (1943; 1947; 1953) and Hudson and Cotton (1945a; 1945b) wrote important contributions on this topic and summaries of these and other papers dealing with the Carboniferous Limestone of north Derbyshire have already been given (pp. 10–1).

Eden and others (1964) described the Pin Dale area and most of the faunas listed by them are included in this account.

The Carboniferous Limestone faunas collected during the present work are dealt with in two parts: first, the shelf facies in ascending stratigraphical order; and second, the marginal province with the reef-limestones. Full faunal lists for the former are given in Appendix 3 (p. 392) and for the latter in (Table 5) (p. 142); the authors of specific names are included in these lists and not repeated in the text unless there is confusion over the names. Only the more important fossils are given in the text and the ranges of some of the stratigraphically significant fossils from the shelf limestones are given in (Table 2) (p. 128). Some forms are illustrated on (Plate 14). The basin facies limestones found in the Alport and Edale boreholes are summarized on p. 113 from the accounts written by Hudson and Cotton (1945a; 1945b). The locality details are given in Appendix 2 (p. 384).

The type section for the Carboniferous Limestone of north Derbyshire is in the Wye valley, east of Buxton, and this was described by Cope (1933) with later additional information (1936; 1937; 1939).

The exposed Carboniferous Limestone ranges in age from the Seminula (S2) Zone to the Upper Posidonia (P2) Zone. In the S2 to Upper Dibunophyllum (D2) Zone part of the succession, the sequence of faunal assemblages is similar to that of the Avon Gorge (Vaughan 1905, pp. 195–9) and the Ashton Park Borehole (Kellaway 1967, pp. 64–8, table 1).

Shelf Province

Woo Dale Beds

The best section of the Woo Dale Beds (p. 40 and Figs. 4, 5) is seen at the junction of Dam Dale and Hay Dale (loc. 3) where 165 ft of these beds are exposed. The lowest diagnostic fauna (loc. 3c) is 13 ft above the base of the section and includes Carcinophyllum vaughani, Davidsonina carbonaria, Daviesiella sp. and Linoproductus corrugatohemisphericus, an assemblage characteristic of the Seminula (S2) Zone (Vaughan 1905, p. 195). Daviesiella sp. also occurs in the bed above (loc. 3d) but these are the only two records of this thick-shelled brachiopod from the present area. The genus occurs more extensively in the Wye valley (Cope 1939, p. 60, fig. 1; 1940, p. 207) where it ranges spasmodically through the undolomitized part of the S2 beds and rarely up into the base of the Chee Tor Rock. The succeeding 129.5 ft of beds (loc. 3e-n pars) yield few significant fossils. Lithostrotion martini, Linoproductus sp. hemisphaericus group and Megachonetes sp. papilionaceus group are the commonest forms with Lithostrotion arachnoideum and L. cf. sociale also present. The zonal position of this assemblage, however, cannot be expressed more precisely than S2 D1; but Semiplanus sp. nov.(of Ramsbottom in Fowler 1966, p. 76) occurs in two beds (locs. 3f, 30. This latter species is considered to be characteristic of high S2 beds in parts of the North-West Province and in Northumberland (see Ramsbottom in Day 1970, p. 171).

The top 11.5 ft of the Woo Dale Beds of this section (loc. 3n pars-p) are marked by the incoming of the typical Lower Dibunophyllum (D1) Zone fauna (Vaughan 1905, p. 198) with the corals Dibunophyllum bourtonense, Koninckophyllum θ and Lithostrotion pauciradiale. This sudden entry of the typical D1 coral fauna at the base of the zone is one of the most consistent features of the Carboniferous Limestone of the South-West Province and all the faunas below this marked change are taken to be of S2 age. In the Dam Dale–Hay Dale section gastropods are relatively common in the basal D1 beds.

A fauna of D1 age is also present in the top 14.5 ft of the Woo Dale Beds at Hernstone Lane Head (loc. 4c, d) where the additional D1 corals Lithostrotion junceum and Palaeosmilia murchisoni have been found.

The best section of Peak Forest Limestones, the lateral equivalent of the Woo Dale Beds, is seen near Hartle Plantation (loc. 8) and the record of L. corrugatohemisphericus confirms the S2 age of these beds. No D1 fossils have been collected from this section but above it a small thickness of unexposed beds is thought to be present, below the base of the Chee Tor Rock, and this may be correlated with the high Woo Dale Beds of D1 age in the southern part of the Peak Forest Anticline.

The distribution of lithologies and D1 faunas in the top part of the Woo Dale Beds is shown in (Figure 5).

Chee Tor Rock

The Chee Tor Rock (p. 43 and (Figure 6)) has D1 Zone faunas throughout. Corals are typically the commonest and most clearly diagnostic fossils, with the assemblage Carcinophyllum vaughani, Dibunophyllum bourtonense, Koninckophyllum θ, Lithostrotion junceum, L. martini, L. pauciradiale and Palaeosmilia murchisoni characteristic of these beds (Vaughan 1905, p. 198). The brachiopods present include Athyris expansa, Davidsonina septosa, Delepinea comoides, Gigantoproductus maximus, Linoproductus sp. hemisphaericus group and Megachonetes sp. papilionaceus group. The last two of these with C. vaughani and L. martini also occur in S2. Gastropods have been commonly noted especially in the lowest 200 ft of the Chee Tor Rock.

The fossils usually occur in well-marked bands a few feet thick and much of the intervening limestone is poorly fossiliferous. The Upper and Lower Davidsonina septosa bands which occur near the top of the Chee Tor Rock are the best known of these bands.

There is no section showing the full sequence through the Chee Tor Rock but (Figure 6) gives a generalized succession. The more important fossil bands are shown on this section with some of the localities at which they occur. In the general account of the Carboniferous Limestone, the Chee Tor Rock has been divided into eight groups of beds for convenience of lithological description (p. 23) and these are used here.

(1) The lowest 40 ft of beds are well exposed in the Hay Dale, Dale Head and Hernstone Lane Head sections and a coral band is developed at the base of the Chee Tor Rock at these localities (locs. 3q, 2f and 4erespectively). The faunas are typical of the D1 Zone and in addition to many of the corals listed above, Caninia cf. densa and Lithostrotion cf. sociale are present. The caninioid is the form noted by Hudson and Cotton (1945a, p. 306) which appears to be restricted to the D1 Zone ((Plate 14), fig. 9). A small gigantoproductoid here named Gigantoproductus? sp. nov. [wrinkled concentric ornament] was found at two of these localities (loc. 3q, (Plate 14), fig. 2; and loc. 2f). Bryozoa are relatively common in this basal band and Cope (1939, p. 62, fig. 1) noted this level as a Polyzoan Bed' in the Wye valley.

(2) The succeeding group of beds, about 160 ft thick, again has a coral bed at the base and this is seen in Hay Dale (loc. 3r); a typical D1 fauna is present. At Dale Head another coral band, 6 ft thick, is developed about 20 ft above the base of this group of beds (loc. 1g) but only a poor fauna is present. The same band is seen in Peter Dale (loc. 19) and here yields a rich fauna. Gigantoproductus ? sp. nov. [wrinkled concentric ornament] is recorded from this horizon and also from about 20 ft higher in the Dale Head section (loc. 1h). The latter is the highest record of this brachiopod which appears to be confined to the lower part of the Chee Tor Rock.

Near Wheston (locs. 22, 23) a minor band occurs about 40 ft higher but yields a poor fauna. This band is probably the same as the one seen on the east side of Hay Dale (loc. 26) where a richer fauna is noted, including D. aff. comoides [transverse form].

With the exception of scattered corals from the highest 20 to 30 ft, no fauna has been collected from the upper part of this group.

(3) An important coral band (about 10 ft thick) with typical D1 fauna is recognized at Laughman Tor (loc. 14b) and bands at or near this horizon are seen on the east side of Middle Hill (loc. 16b) and south-west of Wheston (loc. 24). Scattered fossils are seen in the beds immediately above and below this horizon. Corals are also seen at approximately this level east of Hargatewall (loc. 18) and in Monk's Dale (locs. 20, 21) but it is not possible to make more accurate correlations. In the exposure of this band on the east side of Middle Hill (loc. 16b), C. cf. densa and L. cf. sociale are again present and this is the highest record of the latter species in the district. The locality south-west of Wheston (loc. 24) has yielded specimens of Davidsonina septosa and is the lowest occurrence of this fossil which characterizes the upper part of the Chee Tor Rock.

(4) There are about 80 ft of beds between the coral band of Laughman Tor and the base of the Lower D. septosa Band. The lower beds are seen on the east side of Middle Hill (loc. 16c-e) but only poor faunas have been recorded. On the north-west side of Middle Hill (loc. 17) corals have been collected about 10 ft above the base including Lithostrotion cf. aranea and L. aff. maccoyanum [more septa than typical]. A limited fauna is present at approximately the same level in Oxlow Rake (loc. 29). The uppermost 50 ft of these beds are well exposed in Duchy Quarry (loc. 12a-i). An algal band (loc. 12d) is present about 8 ft above the base of the section and from this a specimen of D. septosa [coated with algae] has been collected. This band is probably developed as a coral band south-west of Wheston (loc. 25) and south of Middle Hill (loc. 15) where the fauna includes Davidsonina septosa and Delepinea aff. comoides [transverse form]. D. septosa is also present in Duchy Quarry (loc. 12i) immediately below the Lower D. septosa Band while at Upperend Quarry it is recorded at this level (loc. 13h) and again about 15 ft lower (loc. 13c).

(5) The Lower D. septosa Band (1 to 4 ft thick) is a well-known marker band with a widespread distribution. Collections have been made from the band in Duchy Quarry (loc. 12j) and Tideswell Moor (loc. 27). The fauna is richer than that found in the Upper D. septosa Band and includes Dibunophyllum bouttonense, Lithostrotion martini, P. murchisoni, Syringopora spp., Davidsonina septosa, Delepinea comoides, D. aff. comoides [transverse form], Gigantoproductus sp., Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group and Straparollus (Euomphalus) sp.

(6) D. septosa is again noted in the 35 to 40 ft of beds between the Lower and Upper D. septosa bands. In Upperend Quarry this species is present at two levels 5 ft (loc. 13l) and 13 ft (loc. 13m) above the Lower D. septosa Band.

(7) The Upper D. septosa Band (1.5 to 5 ft thick) is also well marked and widespread and is correlated with the "Cyrtina septosa Band" of the Wye valley (Cope 1936, p. 48). The best fauna from this band has been collected in Upperend Quarry (loc. 13o) where Dibunophyllum bourtonense, Lithostrotion martini, Syringopora cf. geniculata, Davidsonina septosa, D. septosa transversa, Linoproductus sp. hemisphaericus group, Monograptus sp. papilionaceus group and gastropods are recorded.

Delepinea aff. comoides [transverse form] has been recorded in the Lower D. septosa Band and in two bands (locs. 15, 26) below this level but has not been found in the Upper D. septosa Band during the present survey. Cope (1936, p. 49), however, lists what is probably a similar form from the "C. septosa Band" in the Wye valley.

(8) The beds between the Upper D. septosa Band and the base of the Lower Miller's Dale Lava are 20 to 25 ft thick and except for the records of two more occurrences of D. septosa in Upperend Quarry (loc. 13r, s),the second in association with the subspecies transversa, few fossils are listed.

Miller's Dale Beds

The Miller's Dale Beds (p. 53 and (Figure 6)) contain D1 faunas similar to those of the underlying Chee Tor Rock. Few fossil bands are present and they are less well marked than many of those in the lower formation.

The limestones below the Dove Holes Tuff are seen in Dove Holes Dale Quarry (loc. 31a, b),Holderness Quarry (loc. 32a-c) and Smalldale (loc. 35a-d). Typical D1 faunas are found at these localities and about 30 ft above the base of the Miller's Dale Beds (locs. 31a, 32c, 35d) there is a richly fossiliferous bed from which Davidsonina septosa, D. septosa transversa and Delepinea aff. comoides [transverse form, (Plate 14), fig. 1] have been collected. Jackson (1922, p. 467) recorded Davidsonina septosa and Delepinea aff. comoides from approximately the same horizon, 12 ft above the Lower Lava, in Miller's Dale. Davidsonina septosa transversa and D. septosa have been found together in the present collections both at this level, about 30 ft above the base of the Miller's Dale Beds, and also in and just above the Upper D. septosa Band at Upperend Quarry (loc. 13o, s).Mitchell and Stubblefield (1941, p. 212) recorded D. septosa transversa from beds with B2 goniatites and D. septosa at Breedon Cloud. They suggested that transversa indicated "an horizon higher than that of the C. septosa Band of the North-West Province and Derbyshire". In the present collection, however, the transverse subspecies occurs as low as the Upper D. septosa Band. Parkinson (1965, p. 165) also discusses the records of transversa.

The beds above the Dove Holes Tuff are well exposed in Victory Quarry (loc. 30a-j) but few fossils have been collected from this locality. There is no evidence of the incoming of D2 faunas at the top of the Miller's Dale Beds either here or in the old Peak Forest railway section near the Bull Ring (loc. 33a) where the highest beds are again seen.

The complete sequence of the Miller's Dale Beds is seen at Wall Cliff (loc. 28k-p) but only 63 ft of beds are present between the Lower and Upper lavas. L. cf. maccoyanum [septa withdrawn from a weak axis] has been recorded from 4 ft above the base of the section (loc. 28k). This level is probably the same as the coral bed with L. aff. maccoyanum immediately above the Lower Lava in the Wye valley (Cope 1933, p. 132) and the band with L. cf. arachnoideum and L. aff. maccoyanum recorded by Shirley and Horsfield (1940, p. 276) 20 ft above the Lower Lava in Cave Dale and at Cop Round.

The rare coral Aulina furcata has been recorded (Mitchell 1965, p. 74; Clarke 1966, p. 226) from the lowest bed in the Wall Cliff section (loc. 28k, (Plate 14), fig. 8) and from about 10 ft higher in the sequence (loc. 28m). The type locality of this species is the high B2 limestones of Siggate, Castleton (Smith 1925, p. 494; Smith and Yü 1943, p. 49), and a correlation between the horizon of these two localities is suggested. Clarke considers that this species characterizes a restricted horizon of uppermost D1 (not below "the D. septosa band") and low D2 age.

The higher beds with A. furcata (loc. 28m) also contain a brachiopod fauna including Dielasma hastatum and Pugnax pugnus [small form], species which suggest reef conditions (p. 24) and in the apron-reef belt would indicate a B2 age. The possible link here between reef and shelf faunas is discussed further on p. 152.

Bee Low Limestones

Detailed faunal correlations within the Bee Low Limestones (see also p. 25) are difficult and no additional information about the sequence of D1 faunas is given by this formation.

A well-known coral band is developed in Pindale Quarry (loc. 47f) 32-i ft below the top of the Bee Low Limestones and its fauna was discussed by Jackson (1941, p. 240) and Eden and others (1964, p. 78). In Cave Dale (loc. 45b) the coral Lithostrotion cf. aranea occurs 34.5 ft above the Lower Lava, a horizon that can be correlated with the beds yielding L. aff. maccoyanum in the Wye valley (Cope 1933, p. 132).

Back-reef facies

The Bee Low Limestones are well exposed in the areas to the south of the marginal reef belt and rich reef-brachiopod faunas are present at several localities (Plate 11).

The only goniatite record from these beds is that of Bollandoceras sp. nov., a genus indicating a B Zone age, from Gautries Hill (loc. 39c). The associated reef fauna is poor and not diagnostic. In Eldon Hill Quarry, rich reef faunas are present in a bed with D. septosa (loc. 40b), probably the equivalent of the Upper D. septosa Band of the Chee Tor Rock, and at a second level about 60 ft lower (loc. 40a). Both these reef faunas indicate a B2 age but no clear link is possible with the apron-reef faunas.

Abundant reef faunas have been collected from two other localities. By the roadside south-west of Snels Low, an old quarry (loc. 43a) has yielded Acanthoplecta mesoloba, Dielasma hastatum, Echinoconchus punctatus ((Plate 14), fig. 3), Krotovia spinulosa, Ovatia sp. nov., Pleuropugnoides pleurodon and Plicatifera plicatilis. The Ovatia sp. nov.is the same form as found at Tor Top Sink, Perryfoot (loc. 126a) and Odin Fissure (loc. 135), localities which on goniatite evidence are of high B2 age, and the assemblage from Snels Low is taken to be of this age. The old quarry at the roadside on the south side of Middle Hill (loc. 44b) has a similar fauna and in addition Productus productus aff. hispidus. This is a form of hispidus with only two instead of three rows of spine-bases on the flanks ((Plate 14), fig. 5) and it has been recorded in the apron-reef from the following B2 localities; Perry Dale (loc. 125), Tor Top Sink (loc. 126a), Giant's Hole (loc. 130) and Castleton village (loc. 139).

The horizons of these two back-reef localities (locs. 43a, 44b) within the shelf succession are difficult to establish but they are about 100 to 150 ft below the top of the D1 limestone, near the level of the Upper D. septosa Band, which is exposed a short distance to the east and they cannot be far below this level. If the correlations with the B2 apron-reef faunas are reliable, then these B2 beds can be equated with the limestones about 100 to 150 ft below the top of the D1 Zone.

Lower Monsal Dale Beds

With the exception of the Lower Girvanella Band no well-marked fossil bands occur in the Lower Monsal Dale Beds (p. 63 and (Plate 6)). The faunas are relatively poor, but indicate the Upper Dibunophyllum (D2) Zone. Fossils include Dibunophyllum bipartitum, Diphyphyllum lateseptatum, Lonsdaleia floriformis laticlavia, Gigantoproductus giganteus, Productus productus hispidus, Pugilis pugilis and Striatifera striata, none of which occurs below the base of the Lower Monsal Dale Beds. Some elements of the D1 fauna, including Athyris expansa, Lithostrotion martini and Palaeosmilia murchisoni persist but they are less common here than in the Bee Low Group.

The lower beds are exposed in Victory Quarry (loc. 30k-y), in Cressbrook Dale (loc. 54a-k) and in Earle's Quarry (loc. 70). The Lower Girvanella Band (1.75 to 9 ft thick) is well developed at or near the base in Pin Dale (Jackson 1941, p. 239; Shirley and Horsfield 1940, p. 277; Eden and others 1964, p. 81). Saccamminopsis sp. also occurs in the basal beds and three beds with this fossil have been found in Cressbrook Dale (loc. 54a, g, k),the highest being 45 ft above the base of the Lower Monsal Dale Beds. These two fossils appear to be mutually exclusive for although they have both been collected from the old Peak Forest railway section, Girvanella at the base of the Lower Monsal Dale Beds (loc. 33b) and Saccamminopsis sp. from 26.5 ft above the base (loc. 33d), there is no record of them occurring together in the same bed.

At two localities on the south side of Bradwell Moor, Lithostrotion maccoyanum has been found (locs. 62d, 65) from near the base of these beds.

The higher beds of the Lower Monsal Dale Beds are seen in Cressbrook Dale (loc. 55a-p) and also in Earle's Quarry where the complete sequence (loc. 70a-g) between the Lower and Upper Girvanella bands is seen (Eden and others 1964, p. 81). Few fossils have been noted from this higher group of limestones.

Dark limestones of basin facies with zaphrentoids are seen near Bennetston Hall (locs. 51, 52), and at Barmoor Clough (loc. 50) the P1 goniatite Girtyoceras sp. has been found at a horizon within 20 ft of the base of the Lower Monsal Dale Beds.

There is no development of back-reef limestones as seen in the Bee Low Limestone, but flat reefs occur close to the marginal belt. These can be seen in Earle's Quarry (loc. 70b) at a horizon which is correlated with the P1b beds of Upper Jack Bank Quarry (loc. 142; Eden and others, 1964, pp. 85, 90).

Upper Monsal Dale Beds

The Upper Monsal Dale Beds (p. 75 and (Plate 7)) show a marked change in fauna from the beds below. Several fossil bands are present and some have rich coral faunas. The assemblages, particularly the ones from the Lonsdaleia duplicata and Orionastraea bands are similar to those from the classic D2 localities of the South-West Province (Round Point, Rownham Hill, Wrington; Vaughan 1905, pp. 199–242; Kellaway 1967, p. 64). The corals found in the Upper Monsal Dale Beds include Dibunophyllum bipartitum subspp., Diphyphyllum lateseptatum, Lithostrotion junceum, L. pauciradiale, L. portlocki, Lonsdaleia duplicata, L. floriformis, Nemistium edmondsi, Palaeosmilia murchisoni, P. regia and Orionastraea placenta, and many of these are beautifully preserved. Brachiopods are also common, particularly Gigantoproductus spp.

The sequence of beds is set out on pp. 29–31. The limestones between the bands have relatively few fossils but the faunas of the bands are as follows.

(1) The Hob's House Coral Band (up to 5 ft thick), 50 to 60 ft above the base of the Upper Monsal Dale Beds, is only seen in Cressbrook Dale (locs. 55v, 83a) where Caninia benburbensis, Clisiophyllum sp., Dibunophyllum bipartitum subspp., Diphyphyllum lateseptatum, L. martini, L. pauciradiale, L. portlocki, P. murchisoni and brachiopod fragments have been collected.

(2) The Lower Shell Bed (6 to 7 ft thick) is 50 to 60 ft higher in the sequence and contains abundant specimens of Gigantoproductus edelburgensis in Middleton Dale (locs. 74f, 75c).

(3) The Black Bed (5 to 16 ft thick), 10 ft above the last band, is mainly restricted to Middleton Dale (locs. 73d, 74j, 75g) but is also present in Cressbrook Dale (loc. 83l). It has a limited fauna in which L. floriformis floriformis is the only important fossil. This coral also occurs in the beds immediately above the Black Bed especially at Shining Cliff (loc. 74k) and in Cressbrook Dale (loc. 83m, o).The occurrences of this subspecies are concentrated in this part of the sequence but it is also recorded from the base of the Upper Monsal Dale Beds in Cressbrook Dale (loc. 55r) at the horizon of the Upper Girvanella Band, from the Lonsdaleia duplicata Band in Intake Dale (loc. 88b) and from the Eyam Limestones. Only two specimens of L. floriformis laticlavia have been found, one in the Lower Monsal Dale Beds near Bennetston Hall (loc. 51f) and the other near the base of the Upper Monsal Dale Beds in Cressbrook Dale (loc. 55u).

(4) The Upper Shell Bed (1 to 4 ft thick) is about 25 ft above the Black Bed and as with the Lower Shell Bed can be traced only in Middleton Dale where G. crassiventer and G. dentifer? have been recorded (locs. 741, 75l).

(5) No macrofossils have been collected from the White Bed (up to 7 ft thick) which is 30 to 35 ft above the Upper Shell Bed.

(6) The Lonsdaleia duplicata Band (up to 6 ft thick) is 5 to 30 ft above the White Bed horizon (see (Plate 7) and (Figure 10)) and is well developed in the Bradwell Moor area (Shirley and Horsfield 1940, p. 277). The main elements of the fauna are given in (Table 3). The Dibunophyllum aff. muirheadi Bed (Morris 1929, p. 42) occurs 3 ft above the White Bed at Shining Cliff (loc. 74q). It is of limited extent, and has a fauna which includes Dibunophyllum bipartitum bipartitum (? = D. aff. muirheadi of Morris), D. bipartitum konincki, Lithostrotion junceum, L. pauciradiale, P. regia, G. edelburgensis and Spirifer spp.This bed may be the equivalent of the Lonsdaleia duplicata Band but the correlation cannot be confirmed.

The rich coral faunas of the L. duplicata Band are similar to those of the Orionastraea Band (see (Table 4)). The differences between the faunas of the two bands may not be significant, except that L. duplicata is common at the lower level and has not been found in the upper band; on the other hand Orionastraea placenta is common at the higher level and has not been found at the lower level. Of the species found in the L. duplicata Band and not in the Orionastraea Band, L. duplicata has been found just above the Orionastraea Band both in Furness Quarry (loc. 73u) and at the southern end of Bradwell Dale (loc. 99e); D. furcatum is represented by a single record; L. floriformis floriformis is also found in the Eyam Limestones; while N. edmondsi has not been found above the L. duplicata Band, the only other record of the species in the shelf area being in Cressbrook Dale (loc. 83e) about 80 ft lower in the succession. N. edmondsi has also been found in the Castleton Borehole (see p. 112).

Intake Dale is one of the best localities where the relationships of the L. duplicata (loc. 88b) and Orionastraea (loc. 88i) bands have been seen in the same section. They are separated by 26 ft 8 in of limestones and abundant well-preserved specimens of both corals occur. The record here of L. duplicata duplicata and L .floriformis floriformis together in the L. duplicata Band is unique for this area.

(8) The Orionastraea Band (2 to 3 ft thick) is about 25 to 40 ft above the L. duplicata Band and 30 to 50 ft below the top of the Upper Monsal Dale Beds, and has been described by Shirley and Horsfield (1940, p. 277; 1945, p. 294). The important elements of the fauna are set out in (Table 4).

O. placenta has been found at two horizons outside this band, one at Stoney Middleton (loc. 76a, (Plate 14), fig. 6) 10 ft below the White Bed and the other in Coombs Dale (loc. 77e) about 22 ft above the Orionastraea Band. The specimen of O. aff. indivisa from Stoney Middleton (loc. 76g, (Plate 14), fig. 7) is similar to the form figured by Hudson (1926, pl. 8, fig. 3). O. indivisa is recorded by Shirley and Horsfield (1945, p. 296) from Coombs Dale 25 ft below the Orionastraea Band and (p. 294) an atypical specimen from the horizon of this band at Castle Rock.

Beds with rich reef-brachiopod faunas are sometimes developed in the Upper Monsal Dale Beds. In Coombs Dale (loc. 77c, d) and at the south end of Bradwell Dale (loc. 99d) they occur high in these beds at and above the level of the Orionastraea Band. The brachiopod assemblages are comparable with those found in the overlying Eyam Limestones but are not so richly developed as in these. In the Upper Bench of Earle's Quarry, a 55-ft knoll-reef is seen with its base 26 ft 8 in above the top of the Upper Girvanella Band. The fauna of this knoll (loc. 98) has been described by Eden and others (1964, p. 89).

Eyam Limestones

The Eyam Limestones (Plate 10) contain faunas similar to those of the Monsal Dale Beds. Gigantoproductus spp., Productus productus hispidus and Pugilis pugilis occur while the corals include Aulophyllum fungites subspp., Dibunophyllum bipartitum subspp., Lithostrotion junceum, Lonsdaleia floriformis floriformis, Palaeosmilia regia, Koninckophyllum interruptum and K. magnificum. With the exception of the last two, which Hill (1938, p. 11) lists as occurring only above the Single Post Limestone of northern England (i.e. high in D2), all these species are also present in the underlying beds. The assemblage is indicative of the D2 Zone, and in the absence of goniatite evidence or of correlation with goniatite-bearing beds, would be referred to this coral-brachiopod zone. However, isolated exposures of limestone resting on D1 near Brook House (locs. 121, 122) are correlated with the Eyam Limestones on lithological and faunal evidence. From one of these localities (loc. 122a) the goniatite Sudeticeras sp. has been collected and this dates the Eyam Limestones as of Upper Posidonia (P2) age.

Dark limestones and shales of P2 age, with Rotiphyllum cf. costatum, R. densum, Posidonia corrugata and Sudeticeras sp. are present at Watergrove Mine (loc. 123). Zaphrentoid corals are also recorded from black limestones at Hazlebadge Hall, Bradwell Dale, by Shirley and Horsfield (1940, pp. 286, 288) who correlated these limestones with the dark beds at Ashford and Cawdor Quarry, horizons which are known to be of P2 age.

Two distinctive fossil bands can be traced in the Eyam Limestones, although fossils are common throughout. At Stoney Middleton (loc. 76s) a 1.5-ft band is present about 35 ft above the base with D. bipartitum craigianwn and D. bipartitum konincki. This is the Aulophyllum Band of Morris (1929, p. 54) but A. fungites has not been found here during the present work. The Eyam Dale Coral Band (3 ft thick) can be recognized about 60 ft above the base of the Eyam Limestones in Eyam Dale (loc. 110i). It is widespread in this area and the fauna includes the subspecies bipartitum, craigianum and konincki of D. bipartitum as well as Spirifer spp.

Knoll- and flat-reef limestones with rich brachiopod faunas are found in the Eyam Limestones. However, relatively few species are present although individuals may be common. Most of the species are also recorded from the apron-reef limestones of B2P1a age developed at lower levels. The paucity of species compared with the rich reef faunas in the marginal province may be explained by the environment in the flat reefs of the Eyam Limestones being more restricted than that of the apron-reef front. As an assemblage the fauna is characteristic of the Eyam reef-limestones. The typical association is seen in the reef beds of Intake Dale (locs. 119, 120) where the following fauna has been collected: Acanthoplecta mesoloba, Alitaria panderi, Antiquatonia antiquata, A. hindi, A. insculpta, Avonia davidsoni, A. thomasi, A. youngiana, Brachythyris integricosta, 'B.'planicostata, Buxtonia spp., Dielasma hastatum [juvs.], Echinoconchus punctatus, Eomarginifera lobata aff. laqueata, Girtyella? sacculus, Pleuropugnoides pleurodon, Pugnax pugnus [small form], Schizophoria resupinata and Spirifer (Fusella) triangularis. In addition to these, Antiquatonia sulcata, Krotovia spinulosa(J. Sowerby), Productus productus hispidus, Spirifer (Fusella) trigonalis, S. duplicicosta, bivalves and more rarely gastropods have been recorded from other localities.

Of this fauna only G. ? sacculus is confined to the Eyam Limestones and it is interesting to note that the original locality given for this species was "common in limestone, particularly near Eyem (sic) and Middleton" (Martin 1809, pl. 46, figs. 1, 2).

Marginal Province

A map of the apron-reef outcrop, showing localities from which collections have been made, is given in (Plate 11). Section and locality details are in the text (pp. 105–9) and in Appendix 2 (pp. 390–1). The fossils collected are listed in (Table 5) (pp. 142–8) but this list could almost certainly be extended by further collecting which would probably affect the specific ranges suggested.

Contributions on the geology of the apron-reef have been made by Jackson (1927;1941), 1941), Bisat (1934), Shirley and Horsfield (1940), Ford (1952), Hudson and Cotton (1945a, b), Wolfenden (1958) and Parkinson (1943; 1947; 1953; 1965). The latest paper by Parkinson (1965) is an excellent summary of current views. A further review of the literature is unnecessary and the present account concentrates on the description and interpretation of the new collections that have been made. Acknowledgment must, however, be made of the value of earlier works which form the basis for this account. Wolfenden (1958, p. 871) studied primarily the palaeoecology and the lateral facies and faunal distribution in beds traced from the shelf province into the reef complex, whereas this account attempts to distinguish a sequence of faunal assemblages through the thickness of the reef beds. Wolfenden recognized two horizons at which algal reefs were developed as incipient barriers separating the shelf and back-reef areas from the fore reef and basin areas of deposition.

When goniatites are present in the reef faunas it is possible to establish the following sequence:

Subdivision of B2 has been discussed by Hudson and Cotton (1945a, p. 301) who suggested a division into the two subzones, Beyrichoceras vesiculiferum (lower B2) and B. delicatum (upper B2) with five faunal assemblages, and by Parkinson (1947, p. 123). However, the stratigraphical relationships of the goniatite occurrences are difficult to establish and revision of the B2 goniatite sequences is needed. It is not considered that the available information is adequate to sustain a subdivision of B2(fide Dr. W. H. C. Ramsbottom).

Where goniatites are not present, it is difficult to make faunal distinctions, especially between B2 and P1a beds (Parkinson 1965, p. 162). However, by listing and comparing the faunas where the ages are indicated by goniatites it is possible to distinguish the following changes in the vertical distribution of faunas.

The B2 beds contain the richest faunas ((Table 5)) with an abundance of species and individuals. P1a faunas, especially those inferred to be from low in the zone, are very similar to those from B2, but the P1b horizons show a marked reduction in the number of species present though individuals are relatively abundant. The very extensive faunas from B2 may reflect the greater area of these beds available for collection and the ease with which rich faunas can be obtained.

The species Dielasma hastatum, Pleuropugnoides pleurodon, Pugnax pugnus and Schizophoria resupinata are abundant in B2 beds, less common in P1a and rare or absent in P1b, although all are found in limited numbers in the reef development of Eyam Limestones. P. pugnus is represented by small forms in B2 but in P1b only the larger form (Parkinson 1954, p. 563) has been recorded. Productus productus hispidus has not been found below the base of P1b, but P. productus aff.hispidus [two instead of three rows of spine-bases on the flanks] is present in B2.

Species which are restricted, within the present area, to B2 include Acanthoplecta mesoloba, 'Camarotoechia'trilatera, Echinoconchus aff. punctatus [broad bands, (Plate 14), fig. 4], Leptagonia analoga, Ovatia sp. nov., Overtonia fimbriata, Plicattfera plicatilis, Proboscidella proboscidea, Pugnoides triplex and Sinuatella sinuata (see (Table 5)). Although many of these are known from other horizons outside the Castleton reef-belt, their relative abundance, association with the remainder of the fauna and absence in the immediately overlying P1b beds suggest that they constitute a recognizable B2 assemblage. Corals are almost entirely confined to B2 beds.

Striatifera striata has been collected only from beds of P1a age and is probably the only fossil other than goniatites which can be used to distinguish P1a from B2 faunas. Parkinson (1965, p. 171) notes this species as being of P1a to P1b, age (or very high D1) and the present collection supports the stratigraphical value of this fossil.

The ranges of gastropods, bivalves and other fossil groups are also given in (Table 5), but apart from the fact that they are again more abundant in B2, especially at Treak Cliff, little can be concluded.

The following list gives the significant elements of the faunas from each of the reef localities and the arguments for their suggested ages.

Loc. 125, Perry Dale. Only a small collection was made from this locality, but the presence of Productus productus aff. hispidus suggests a B2 age.

Loc. 126, Tor Top Sink, Perryfoot. Collections have been made here from two horizons in the apron-reef. The lower horizon (loc. 126a) contains Ovatia sp. nov., P. productus aff. hispidus and the goniatites Beyrichoceras sp. [rectangularum or delicatum, cf. Bisat 1934, fig. 17, p. 288] which indicates a high B2 age. The upper horizon (loc. 126b) has a rich fauna of P1a age including Goniatites sp. crenistria group and Striatifera striata.

Loc. 127, valley between Snels Low and Middle Hill. Leptagonia analoga, Overtonia fimbriata and Spirifer striatus are present and the fauna is of B2 age.

Locs. 128a to 134 Peaks Hill, Giant's Hole. This series of localities is from the complex area on the north side of Middle Hill (Parkinson 1943, p. 125; 1947, p. 107).

Loc. 128a, west side of Peaks Hill. The only specimen collected is the B2 species Goniatites wedberensis Bisat. The locality is not listed in (Table 5).

Loc. 129, near west side of Peaks Hill. A relatively limited reef fauna from here is probably of B2 age.

Loc. 130, Peaks Hill. A B2 fauna has been collected from this locality with L. analoga, P. productus aff. hispidus, Goniatites crenistria [early form, cf. GSM 86644 from Black Hole, Malham], and G. cf. hudsoni [cf. Bisat 1952, pl. 2, fig. 6]. The goniatite evidence suggests that this horizon is near the top of the B2 Zone.

Locs. 131–134, Giant's Hole. No goniatites have been collected from these localities and the reef faunas, although of B2 aspect, are too indefinite to be included in (Table 5). Palaeosmilia regia, however, is recorded from locality 131 and the significance of this coral is discussed below (p. 152).

Loc. 135, Odin Fissure. A rich B2 fauna is present and includes the goniatites Beyrichoceras rectangularum, Bollandoceras cf. micronotum and Goniatites sp. (Parkinson 1947, p. 110; 1953, p. 258; 1965, p. 162).

Loc. 136a-w, Treak Cliff: This is the classic collecting locality of the Castleton area. An extensive collection was made from a series of exposures across the width of the apron-reef, (a) being at the top of the Treak Cliff slope and (w) at the base of the slope near the limestone-shale junction (see inset map on (Plate 11)). Only a few poorly preserved goniatites were found, but the locality has long been famous for its isolated pockets of these fossils. The goniatite fauna listed by Parkinson (1947, p. 107) is of high B2 age and there is no evidence of P1a being present. The richest faunas are found on the higher parts of the apron slope associated with the algal-reef limestones (Wolfenden 1958) which form the crest of Treak Cliff, and where presumably the widest range of ecological niches existed. Juvenile specimens are common at many localities and deformed shells are also found throughout the fauna. The shell damage is of the kind described by Brunton (1966, p. 355, p1. 60, figs. 4, 5) where the normal growth is distorted and the shell scarred to the anterior border. Brunton suggests that fishes may be responsible for crushing the shells. Fish remains are not here recorded from Treak Cliff but the mandible gnathal lobe (18 mm long, with six tooth-like projections on the crushing surface) of the crustacean Dithyrocaris has been found at locality 136c ((Plate 14), fig. 10) and this animal may have caused some of the shell damage.

Echinoderm remains, except for crinoid columnals, are very rare in the Castleton reefs and this contrasts with their abundance in the reef-limestones of the basin province at Clitheroe. Wolfenden (1958; 1959) records two species of sponges from the algal reef at Treak Cliff.

A specimen of the rare fossil 'Michelinia' balladoolensis J. Smith (1911, p. 148, p1. 25, fig. 18) was collected from Treak Cliff [SK 1341 8333] and presented to the Institute of Geological Sciences by the Rev. Fr. MonograptusE.R. Le Morvan in 1965. The species, which is at present known only from three localities, is not a tabulate or rugose coral. Affinities either with the Conulariidae or with the Bryozoa are suggested. The type material comes from the Carboniferous Limestone ( ? B2 reef) of Balladoole, Isle of Man, and 24 fragments of the species are present in the C. B. Salter Collection (I.G.S.) from the Hotwells Limestone (D2) of Compton Martin, Mendip Hills.

Loc. 137, Winnats. An extensive B2 fauna is recorded and Ovatia sp. nov., Overtonia fimbriata and Plicatifera plicatilis are present.

Loc. 138, Cow Low Nick. Ford (1965, p. 186) listed a B. goniatite fauna from this locality which is placed in "lower B2" by Parkinson (1965, p. 164) on stratigraphical grounds.

Loc. 139, S.W. of Castleton church. The reef fauna here includes Echinoconchus aff.punctatus, L. analoga and P. product us aff. hispidus, and is similar to the typical B2 faunas from Treak Cliff.

Loc. 140, ledge above entrance to Pindale Quarry. Eden and others (1964, p. 90) correlated this locality with the P1b beds of Upper Jack Bank Quarry, but a specimen of Pugnax pugnus [small form] is present, and the limestones forming the floor of this ledge may be older than P1b).

Loc. 141, Lower Jack Bank Quarry. Reef-limestone of both P1a and P1b age are developed (Eden and others 1964, p. 90). Poorly-preserved goniatite fragments are present at the lower level (loc. 141c) and one specimen shows "crenulate transverse ornament" diagnostic of the P1a species G. crenistria. Striatifera striata is also present. The upper horizon (loc. 141d) is equated both on fauna and geometry with the P1b beds of the apron slope.

Loc. 142, Upper Jack Bank Quarry. Goniatites striatus, figured from here by Bisat (1934, pl. 18, fig. 1), dates the beds as P1b and the fauna also includes P. productus hispidus.

Loc. 143, Nunlow Quarry. A small outcrop (loc. 143a) at the base of the quarry has a rich reef fauna of B2 age including L. analoga, Plicatifera plicatilis, Proboscidella proboscidea and Spirifer striatus. The higher beds are difficult to relate and are not richly fossiliferous. However, locality 143b with Striatifera striata is thought to be of P1a age and the highest beds (loc. 143c) are of P1a or low Pit, age.

Loc. 144, Mich Low. Parkinson (1947, p. 111) records G. striatus from Mich Low and the fauna with Product us productus hispidus and Pugnax pugnus [large form] is of P1b age.

Loc. 145, near Bath Cottage. Brachymetopus maccoyi is recorded here and the only other locality where it has been found is Mich Low. Pugnax pugnus [large form] is also present at both localities, which are of P1b age.

Loc. 146, near Bath Cottage. A small exposure about 100 yd west of the previous locality has a limited PA, fauna in which Pugnax pugnus [large form] is the only brachiopod of significance.

Loc. 147, near New Bath Hotel. A rich fauna has been collected which differs from that of the previous two localities and is of the B2 type.

From a comparison of the apron-reef localities, the faunas which are suggested as typical of the three major reef horizons are as follows:

A change occurs in the distribution of reef-limestones along the line of Dirtlow Rake in Pin Dale. To the west of this line almost the whole of the apron-reef limestones are of B2 age and only the upper beds at Tor Top Sink (loc. 1268) are of P1aage. To the east of Pin Dale the apron slope is formed of P1b reef-limestones resting on D1 shelf limestones. B2 reef, which is only seen in isolated exposures at Nunlow Quarry (loc. 143a) and near the New Bath Hotel, (loc. 147) is not present over much of the eastern area.

This change of distribution is further emphasized by the presence of well-developed back-reef beds west of this line, while none is present to the east. Dirtlow Rake throws down about 75 ft to the east and whereas the top 50 ft of D1 are seen in Pindale Quarry and show no development of apron-reef limestones, the D1 shelf limestones seen to the west of Pin Dale may be more than 75 ft below the top of the zone and show extensive apron-reef development at several levels. It is possible, therefore, that no reef-limestones were formed corresponding with the highest beds of D1 that the main mass of BE apron-reef correlates with limestones some way below the top of D1 and that there is a faunal break between the B2 and P1b reefs. The differences between B2 and P1b faunas support this latter suggestion but the placing of the P1a faunas is not clear.

There has been a long-standing controversy about the relationship of the coral-brachiopod and goniatite zones, but the general equivalence of D1 with B2 and lower D2 with P1a–b has been accepted since the works of Hudson and Cotton (1945a, b) and Parkinson (1943; 1947); see also discussion of Shirley and Horsfield (1940, pp. 296–9).

The Pindale Quarry section shows the lateral passage of P1b apron-reef limestone into the shelf sequence at a horizon about 28 ft above the base of D2 (Eden and others 1964, p. 90). The B2 limestones are seen both on faunal and geometrical grounds to be the equivalent of beds high in the D1 Bee Low Limestones in the Middle Hill and Snels Low areas (p. 136), and Aulina furcata, which occurs at Siggate in high B2 beds and at Wall Cliff (loc. 28k, m) in the Miller's Dale Beds (high D1) is a further link between B2 and high D1 zones. The position of P1a is therefore critical and is unfortunately the most difficult to relate.

Eden and others (1964, p. 90) considered that P1a beds "represent either the bottom few feet of D2 or the top part of D1". The presence in P1a of Striatifera striata, which has only been recorded from lower D2 beds in the shelf limestones, suggests that P1a is probably not below the base of D2. On this basis P1a correlates with part of the 28 ft of pre-P1b present at the base of D2 in Pindale Quarry. Moreover, the occurrence of Palaeosmilia regia at Giant's Hole in beds which on goniatite evidence are high B2 (Parkinson 1943, p. 126), agrees with P1a being also above the base of D2. This coral is not known below the base of D2 and, as shown by Parkinson (1947, fig. 1), B2 probably overlaps with D2. However, if Wolfenden's (1958, p. 881) record of P. regia "at all horizons in these (B2) limestones" is accepted then this correlation cannot be correct. The placing of P1a in D2 differs from that suggested by Bond (1950b, p. 179) for the Cracoe reefs where "Lower P1a is correlated with Upper D1".

The boreholes at Castleton and Hope close to the apron-reef are included in the Marginal Province and details are given on pp. 111 and 112. In the Castleton Borehole, mudstones of P2 age are found to 114 ft 6 in and limestones to the base of the hole at 203 ft 6 in. Rolled shell fragments are present from 139 ft 3 in to 203 ft 6 in and the lithology especially below 172 ft 6 in is typical of the Beach Beds. As at outcrop, the fauna consists of Gigantoproductus and Spirifer fragments and the only evidence of age is given by the coral band from 167 ft 3 in to 169 ft 7 in. The corals present include Aulophyllum fungites, Diphyphyllum lateseptatum, Lithostrotion portlocki and Nemistium edmondsi and suggest a position in the shelf sequence near the L. duplicata Band, high in the upper part of the D2 Zone. In the Hope Cement Works Borehole Lonsdaleia duplicata duplicata and zaphrentoid corals are present from 299 ft to 310 ft 8 in and again this level is correlated with the L. duplicata Band.

Basin Province

The Alport and Edale boreholes proved parts of the Lower Carboniferous succession in the Basin Province and the faunas are summarized on pp. 113–9. MonograptusMonograptus

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Chapter 4 Millstone Grit Series (Namurian)

Introduction

The Millstone Grit Series crops out over three-quarters of the Chapel en le Frith district. In the north it forms a broad tract including the plateau, of Kinder Scout and adjacent moorlands. Farther south, relatively narrow outcrops lie between the Coal Measures of the Goyt Trough and the Carboniferous Limestone of the Derbyshire Dome. In the west it is exposed in the Todd Brook and Romiley anticlines, and in the east, the outcrop, narrowing southeastwards, separates the Carboniferous Limestone outcrop from the Coal Measures of the East Midlands Coalfield. Within the limestone area shales of early Millstone Grit age form an outlier at Wardlow Mires.

In the north much of the Millstone Grit Series, here some 4000 ft thick, is comparable with that of the Holmfirth and Glossop (Bromehead and others 1933) and the Huddersfield and Halifax (Wray and others 1930) districts. In the south-west, however, it shows many features in common with the Millstone Grit of the Staffordshire area (see for example Evans and others 1968). The south-eastern outcrops show the same southerly thinning as that noted around Sheffield (Eden and others 1957) and Chesterfield (Smith and others 1967).

Previous Research. Whitehurst (1778, p. 147) first introduced the term Millstone Grit in the Derwent valley, to the south of the present district, for a coarse sandstone (evidently the Ashover Grit) separated by shales from the Carboniferous Limestone. This description was followed and elaborated by Farey (1811) who recognized that these beds lie beneath the Coal Measures and are of generally similar character to them though lacking important seams of coal. Farey also noted the presence beneath the "Millstone Grit" of a lower series of sandstones which he termed the "Shale Grit" (ibid., p. 228) underlain by shales, the latter overlying the limestone. He also discussed the production of millstones, then as important in the present district as in the country to the south.

In 1864 Hull and Green described the Millstone Grit of the whole of the west Pennine area including Kinder Scout and the ground around the Goyt Trough. Their succession was:

These authors were apparently much influenced by the coarse, massive character of the Kinderscout Grit for they remark (p. 247) that "Were it not that the Kinder Scout Grit makes so natural and so generally received a base to the Millstone-grit, the first of these groups [i.e. the Shale Grit] might well have been placed in that formation rather than among the Yoredale Rocks."

The sucession of Hull and Green was the basis of that used in two Geological Survey memoirs. The first of these (Hull and Green 1866) dealt with an area which included the country to the west of Chapel en le Frith, whereas Kinder Scout and the eastern outcrops fell within the region described by Green and others (1887). Although it was possible over the greater part of the area to correlate much of the Millstone Grit on a lithological basis (the only means then available), there were places where rapid lithological variation of the grits or faulting led inevitably to mis-correlation. Thus for example the Roaches Grit which was assigned to the 3rd Grit has since been shown to lie beneath it (Cope 1946, p. 142). Confusion also arose regarding the upper limit of the Millstone Grit due to the mistaken equation on lithological grounds of the Yard Coal of the New Mills area (in fact the Bassy Mine) with the Sand Rock Mine of Lancashire.

The unconformable nature of the junction between Millstone Grit shales ("Yoredale Beds") and Carboniferous Limestone was noted by Barnes and Holroyd as early as 1897. Anomalies in the relations between the two formations had been previously explained by faulting (see Old Series One-inch Sheet 81 N.E., published 1866).

The memoir on the northern part of the Derbyshire Coalfield by Gibson and Wedd, published in 1913, described the more important features of the Millstone Grit succession on the eastern edge of the district. The "Kinderscout Grit" of these authors has since been shown to be the Ashover Grit (Smith and others 1967, p. 68) and their "Longshaw Grit" has been proved to be the Rough Rock (Eden and others 1957, p. 18).

In a series of papers between 1923 and 1927 Jackson divided the lower part of the Millstone Grit in and around the Edale area into (in upward succession) Edale Shales, Mam Tor Sandstone, Shale Grit, Grindslow Shales and Kinderscout Grit. He recognized many of the faunal horizons, showed that the so-called Yoredale Beds were not the equivalent of those of north-west Yorkshire, and demonstrated the extent of the unconformity at the base of the Millstone Grit. Such advances in knowledge of the Millstone Grit were made possible by the pioneer work of Bisat (1924) on the Carboniferous goniatites of the north of England.

Knowledge of the relations between limestone and shale near the borders of the stable block (see p. 11) was further increased by Fearnsides and Templeman who, in 1932, described the succession in a borehole at Hope Cement Works. These authors recognized the presence of Eumorphoceras bisulcatum Girty in the higher part of the Edale Shales, though the fauna and zonal position of the lower beds have been re-interpreted in the present memoir (see pp. 200–1).

Stratigraphical work in more recent years has been limited to two important papers by Hudson and Cotton. These describe the successions in boreholes for oil, at Alport (1943) and Edale (1945) respectively. Both papers are quoted widely below.

In 1946 Cope gave a detailed description of contorted beds (see p. 161) in the Millstone Grit and Lower Coal Measures of the southern part of the Goyt Trough, partly within the present district.

Following the development of sedimentology in recent years, parts of the Millstone Grit have been studied by Allen (1960) who described the 'Mam Tor Sandstone', and Walker (1966) who studied the Shale Grit of the Alport area. Walker classed the Shale Grit and Grindslow Shales together as the "Alport Group"; this term has not been found applicable in the more extensive area covered by this memoir. Deep channels cut into the upper Grindslow Shales and filled with coarse sandstone which forms the basal Kinderscout Grit are considered by Collinson (1970)Collinson, J. D. 1970. Deep channels, massive beds and turbidity current genesis in the central Pennine basin. Proc. Yorks. geol. Soc., 37,495–519. to be of fluviatile origin.

Classification

The Millstone Grit Series is synonymous with the Namurian. The lower limit of the series is defined at the entry of Cravenoceras leion Bisat; the top is defined as the base of the Gastrioceras subcrenatum Marine Band.

The chief divisions of the Millstone Grit in the present district (see also fig. 15) are as follows:

Approximate thickness in feet

Rough Rock Group: Yeadonian (Lower Gastrioceras Age)

G1

Six-Inch Mine or Pot Clay Coal

G1b

50–150

Rough Rock and Rough Rock Flags

G1b

Shales with Gastrioceras cancellatum Marine Band at base

G1a–G1b

100–280

Middle Grit Group: Marsdenian (Upper Reticuloceras Age)

R2

Shales with Redmires Flags, Simmondley Coal and Ringinglow Coal

R2c

55–140

Chatsworth Grit

R2c

25–150

Shales with Roaches Grit and Corbar Grit (or Ashover Grit) and Heyden Rock; Reticuloceras gracile Band at base

R2a–R2c

300–1500

Kinderscout Grit Group: Kinderscoutian (Lower Reticuloceras Age)

R1

Kinderscout Grit

R1c

100–500

Shales

R1c

100–400

Shale Grit

R1c

0–700

Mam Tor Beds

R1c

0–450

Upper part of Edale Shales with Homoceras magistrorum Band at base

R1a–R1c

150

Beds below Kinderscout Grit Group: Alportian, Chokierian, Arnsbergian and Pendleian (Homoceras H2 and H1, and Eumorphoceras E2 and E1 ages)

H1, H2, E2 and E1

Lower part of Edale Shales; beds with Cravenoceras leion at base

700

For descriptive purposes in this memoir it is most convenient to describe the Kinderscout Grit Group and underlying beds together so that the Edale Shales can be dealt with as one unit. I.P.S.

Faunas

The marine faunas usually consist of non-benthonic bivalves and goniatites, but they are restricted in their occurrence to that part of the faunal cycle which is interpreted as representing times of maximum salinity (seep. 164). The goniatite stages, zones and subzones now recognized are given in the table below which differs in certain respects from the zonal scheme used by Hudson and Cotton (1945); see also Evans and others (1968, p. 21).

Stage

Zone

Subzone

Yeadonian (G1)

Gastrioceras cumbriense (G1b)

G. cancellatum (G1a)

G. crencellatum

G. cancellatum

G. branneroides

Marsdenian (R2)

Reticuloceras superbilingue (R2c)

Donetzoceras sigma

R. superbilingue

R. bilingue (R2b)

R. metabilingue

R. bilingue

R. gracile (R2a)

Kinderscoutian (R1)

R. reticulatum (R1a)

R. coreticulatum

R. reticulatum

R. nodosum (R1b)

R. nodosum

R. dubium

R. circumplicatile (R1a)

R. todmordenense

R. circumplicatile

Alportian (H2)

Homoceratoides prereticulatus (H2c)

Ht. prereticulatus

H. eostriolatum

Homoceras undulatum (H2b)

Hudsonoceras proteus (H2a)

Chokierian (H1)

Homoceras beyrichianum (H1b)

H. subglobosum (H1a)

Arnsbergian (E1)

Nuculoceras nuculum (E2c)

N. nuculum

N. stellarum

Cravenoceratoides nitidus (E2b)

Ct. nititoides

Ct. nitidus

Ct. edalensis

Eumorphoceras bisulcatum (E2a)

E. bisulcatum

C. cowlingense

Pendleian (E1)

Cravenoceras malhamense (E1)

E. pseudobilingue (E1b)

C. leion (E1a)

E. hudsoni

E. stubblefieldi

E. tornquisti

In E1, E2a and R1c to G1 the goniatite-bearing horizons are very distinct and are usually separated by unfossiliferous beds. But from E2b to R1b there is only a small total thickness of unfossiliferous beds, the goniatite horizons are closer together and the succession is almost wholly marine, even between the goniatite horizons, where mollusc spat is common (Ramsbottom, Rhys and Smith 1962, p. 115). Most of the faunas have been described in greater detail from the Clitheroe district by Ramsbottom in Earp and others (1961, pp. 186–95).

Benthonic faunas of brachiopods, crinoids, trilobites, etc. are known only from a few horizons, as for example in the basal E1 beds, in places at the horizon of C. malhamense, at the Ct. nititoides horizon, and in the Butterly Marine Band where the fauna consists of benthonic bivalves and gastropods as well as brachiopods.

Non-marine faunas are restricted in this district to R2 and G1. It is worth noting that the record of Carbonicola in the unusual lithology of the Heyden Rock constitutes the earliest record of the genus in the Pennine area. W.H.C.R.

Lithology

The sandstones form the most striking feature of the Millstone Grit, being much better exposed than the shales, and forming much bolder features; they are, however, less important so far as thickness is concerned. Following the account of the Millstone Grit sandstones of the Bradford area by Dunham (in Stephens and others 1953) it is now customary to avoid the use of the term 'grit' in the lithological descriptions of these rocks, as it implies an angularity of grain which is not always present; it is retained for historical reasons in the stratigraphical names.

The coarser sandstones of 'fluvial-grit' lithofacies (see p. 162) are highly feldspathic, commonly pebbly, cross-bedded, and in places conglomeratic. The pebbles are usually quartz although feldspar occurs rarely. The medium- to coarse-grained sandstones (such as the Shale Grit and parts of the Roaches Grit) show a different development with massive sandstone beds, rarely cross-bedded, but with sole-marks, particularly large load-casts. Thin partings of flaggy sandstone, siltstone or shale separate the thicker sandstone beds.

Fine-grained sandstones and siltstones are developed at some horizons, the best examples being the Rough Rock Flags and Redmires Flags, though both are of local development only. The finer-grained sandstones are frequently micaceous, thin-bedded and flaggy. A development of alternating thin sandstones and shales which forms the Mam Tor Beds has been described as of 'turbidite' lithofacies (see p. 173).

Quartzitic sandstones are present in the lower part of the succession in the south-west of the area. These may be conveniently termed 'crowstones', the name given to similar beds in the Staffordshire area. The use of the term 'crowstone' has been recently criticized by Holdsworth (1964) largely on account of its misuse by Hudson and Cotton (1943). There seems, however, no need to discard it for the thick quartzitic sandstones of Staffordshire, for which it was originally used by Hull and Green (1866, pp. 9, 67), and for similar beds in the present district.

In this account the argillaceous rocks are usually described as 'shale', the term 'mudstone' being restricted to rocks which can be seen to be poorly or non-fissile. A variety of types, many of which grade into each other, is present: the most frequent is a grey shale of moderate fissility, but micaceous, silty or sandy shales also occur. Shales which are otherwise free of silt-grade material may contain abundant mica flakes. Marine bands, rarely exceeding a few feet in thickness (in the upper, predominantly non-marine beds), show in many cases a lithology different from that of the non-marine shales, being either more calcareous and blocky, or darker and more regularly fissile.

Ironstone bands and nodules are of frequent occurrence in the grey shales. Limestone is present as bands or lenses in the lower, marine part of the sequence and as bullions (concretions), associated with the marine bands in the upper part. Pyrite also occurs in the marine shales, and sometimes also in the associated unfossiliferous shales. Frequently shales of marine or quasi-marine type present a yellowish 'sulphurous' appearance when weathered. Hartley (1957, pp. 19–23) showed that similar 'sulphurous' weathering in shales of Viséan, Namurian and Lower Coal Measures ages in Yorkshire was due to the presence of the secondary mineral jarosite, resulting from the decomposition of pyrite.

Coals are present at four horizons in the upper part of the Millstone Grit, though the lowest (that below the Butterly Marine Band) is known from one locality only. They are usually thin, the greatest thickness known in the present district being 30 in for the Simmondley Coal. Despite their locally pyritous nature the three main coal horizons have all been worked in places, though often in conjunction with the underlying seatearth. Seatearths or ganisters are usually present beneath the coals, or may mark their horizon when the coal is absent. Many of the thicker grits have a small thickness of ganister or ganister-like sandstone at the top and in one place (see p. 234) ganister is present within the Chatsworth Grit, perhaps marking a split into two cyclothems.

A remarkable feature of the Millstone Grit succession in the area of the Goyt Trough is the presence of thin contorted bands in the shales, usually at constant horizons. These beds were first described in detail by Cope (1946, pp. 139–76) who found that they were closely associated with, and usually just above marine bands. Cope noted eight such beds in the part of the Millstone Grit succession above the Reticuloceras bilingue Band. In the ground lying south of Whaley Bridge within the present district he noted contorted bands above the Gastrioceras cancellatum and above the G. cumbriense bands. Following an analysis of the structural features (shear-planes and small folds) present in the bands, Cope concluded that they were of tectonic origin and resulted from bedding-plane slip in the least competent beds in the succession during folding.

Additional contorted beds have been found during the present work in the Edale Shales, particularly near the junction with the Carboniferous Limestone. Similar beds are also present in the Coal Measures (see p. 267).

Sedimentation

The Millstone Grit was laid down in two contrasting areas: (a) a 'negative' area of thick sedimentation extending from the Alport valley through Kinder Scout to the area now occupied by the Todd Brook Anticline and from thence into North Staffordshire. In this basin of deposition the overall thickness of the Millstone Grit varies from about 3500 ft at Alport and 4000 ft at Kinder Scout to perhaps 5200 ftThis fig. is based partly on the estimate of 1800 ft for the total average thickness of the E1 and E2 stages in the Macclesfield district (Evans and others 1968, p. 19). in the Todd Brook Anticline. Owing to lack of information regarding the thickness of the lower beds, it is not possible to define the northern and western limits of this basin, but it probably extended north-westwards into the Rossendale and Bradford areas. In this area of sedimentation evidence from the Alport and Edale boreholes shows a conformable relationship between Namurian and Viséan rocks; (b) a 'positive' area of thin sedimentation over the Derbyshire Dome, coinciding broadly with the present outcrop of the Carboniferous Limestone. Although Namurian sediments are rarely present over the area, thinning in these beds can be observed in many places as the Dome is approached. The basal unconformity (see below) of the Namurian provides additional evidence of the 'positive' influence of the limestone massif. Outcrops of Namurian on the massif at Great Hucklow and in the outlier at Wardlow Mires show a strongly condensed succession. Round the edges of the Derbyshire Dome there is, in addition to the thinning noted above, a general tendency for thinning to the south, largely accounted for by the southerly disappearance of many of the 'grits'.

The pattern of sedimentation shows a marked vertical variation as follows:

(a) The Edale Shales show uniform conditions with the quiet deposition of marine muds and only minor incursions of coarser sediment. These beds show cyclic sedimentation, with a repetition of faunal phases (see p. 164) as noted by Ramsbottom, Rhys and Smith (1962, pp. 114–7) in the Ashover area. These cycles, being of the type ABCDCBA, however, differ in arrangement from the sedimentary cycles of the higher beds (ABCDABCD); (b) The Mam Tor Beds and Shale Grit represent, respectively, the earlier and later stages of the advance into the area of a fan of 'turbidite' deposits on the frontal slopes of a delta-fan coming from the north; (c) The main part (see below for beds of different facies) of the Kinderscout Grit is of the 'fluvial-grit' type of Trotter (1952, pp. 78–9) and represents the incursion from the north of the main mass of the delta-fan. The top of this part of the Kinderscout Grit is in many places ganister-like, and in one place shows a thin coal. Thus, by this time, the basin had been largely filled, allowing the establishment of more uniform conditions of cyclic sedimentation; (d) The beds above the Butterly Marine Band, where the Kinderscout Grit is split, or above the base of the Reticuloceras gracile Band, where the grit is united, show the characteristic Millstone Grit cyclic sedimentation.

The sedimentary cycles or cyclothems are similar to those described in the Chesterfield area (Smith and others 1967, pp. 5, 80–1), and may be summarized thus:

The cycles are often incomplete with one or more elements missing and others expanded. In some cases (e.g. the Chatsworth Grit) the sandstone element is coarse and massive and of 'fluvial-grit' facies. The R2 and G1 stages are made up of about 8 to 10 cycles and these vary in thickness from as little as 15 ft (beneath G. cancellatum Band) to 320 ft (beneath G. cumbriense Band in the Goyt Trough).

The Basal Unconformity

The importance of this feature was first recognized by Barnes and Holroyd (1897, pp. 125, 129). Its widespread nature was confirmed and its vertical extent determined by Jackson (1925, 1927). Hudson and Cotton (1945, p. 14), referring to the area south of Mam Tor, stated that Reticuloceras occurred in a pocket of shale on the limestone surface. No precise locality was given for this occurrence, despite its importance. It is difficult to reconcile the record with the presence of E2c. faunas high in the landslip at Mam Tor and well above the limestone in a stream north of Perryfoot. Perhaps the shale from which Hudson obtained the Reticuloceras was not in situ; however, if correct, it would indicate a greater amount of overlap than anywhere else in the district.

The present work confirms the presence of an angular unconformity at the Namurian–Viséan junction at most places where it is seen at surface within the present district. Whether the record of Reticuloceras quoted above is accepted or not, it is evident that the salient of Viséan near Mam Tor stood out as a headland or shoal and as an area of non-deposition during E1 and part of E2 times (and possibly longer) and was progressively buried, producing an unconformity with large overstep. Where differences in the relief are not too pronounced, as at Windy Knoll and around Brook House near Buxton, the Namurian shales, instead of being steeply banked against the limestone, occupy erosional hollows on its upper surface.

Simpson and Broadhurst have demonstrated (1969) the presence of a boulder bed at the base of the shales overlying the apron-reef at Treak Cliff. This bed has resulted from the downhill movement of large masses of limestone on the steeply-inclined frontal slope of the apron-reef and their incorporation into the mudstones. The concept, adopted here, of the gradual burial of the apron-reef during early Namurian times suggests an E1 age for the boulder bed at Treak Cliff in view of its position on the reef slope. Minor features associated with the unconformity include 'Neptunian dykes' of shale and breccia in the limestone at Treak Cliff, Castleton (Ford 1952, pp. 352–3) and of shale in the limestone at Windy Knoll, near Mam Tor, and the local concentration of uraniferous phosphate on the uppermost surface of the apron-reef limestone at Castleton (Peacock and Taylor 1966, pp. 19–32). Similar concentrations of phosphate have been found associated with breaks in sedimentation in other places. For example, Dietz, Emery and Shepard (1942, pp. 815–47) have described the phosphatization of the walls of steep escarpments and submarine canyons off the coast of southern California, all in areas of non-deposition. This probably presents a fairly close parallel to the conditions obtaining prior to the deposition of the Edale Shales in the reef area.

Where shale of Viséan (P2) age is present beneath the Namurian, as in the Castleton Borehole (see p. 111) and in the Wardlow Mires outlier, there is no evidence of an unconformity between the two and the stratigraphical break is at the base of the P2 shale. The intra-Carboniferous movements involved form part of those distinguished by Hudson and Mitchell (1937, pp. 28–31) as 'Sudetian' in the area of the Skipton Anticline (see also p. 322); they do not, however, coincide precisely with any of the three phases of movement noted by these authors.

General stratigraphy

Kinderscout Grit Group and underlying beds (Pendleian, E1 to Kinderscoutian, R1)

These strata are described together, as the uppermost part of the Edale Shales is included in the Kinderscout Grit Group, and it is convenient to describe these shales under one heading. The lower subdivision extends upwards from the base of the Cravenoceras leion Zone to the base of the Homoceras magistrorum Band (see (Plate 15)) and the Kinderscout Grit Group, from thence to the base of the Reticuloceras gracile Band (see (Plate 17)).

Edale Shales

The Lower Carboniferous is succeeded by a group of marine shales which is best exposed in the Edale valley (see fig. 16). These have been called the Edale Shales by Jackson (1923, p. 307) and the name can be appropriately used throughout the present district though their top, marked by the incoming of sandy beds of R1 age (Mam Tor Beds, Shale Grit or Kinderscout Grit), is diachronous, even in the type area. The zonal succession is set out on p. 159 and the stratigraphy is described under these headings below. It should be noted that the present zonal boundaries do not everywhere coincide with those used by Hudson and Cotton (1943, 1945). These authors also used the term 'Edale Shale' in a more restricted sense in the Alport and Ashop valleys.

The Edale Shales are about 800 ft thick in the type area where the detailed succession is well exposed in stream sections except for the lowest beds which were proved in the Edale Borehole (Hudson and Cotton 1945). In the Alport valley a thicker succession totalling 1220 ft has been found in surface exposures and in the Alport Borehole (Hudson and Cotton 1943).

The chief lithological types within the Edale Shales are as follows:

  1. Soft grey shale, poorly fossiliferous or unfossiliferous and often showing 'sulphurous' weathering, resulting from the alteration of pyrite. These shales contain ironstone bands and nodules in places, but limestone bands or nodules are rare or absent.
  2. Dark shales, usually calcareous and with an abundant fauna. Thin limestone bands, up to a few inches thick, are present in places, and bunions up to 3 ft diameter occur at some horizons (particularly in H and R1). At one horizon (see pp. 189–91) a thin bed of dolomitic siltstone and dolomite is present.
  3. Silty shales occur in part of E1. These contain interbedded thin quartzitic siltststones in the Alport Borehole where they have been given the name "Alport Crowstones" (Hudson and Cotton 1943, p. 147) but, as Holdsworth (1964) has pointed out, the use of the term 'crowstone' is here inappropriate as these rocks are quite unlike the typical 'crowstones' of the Staffordshire area (see for example Evans and others 1968, pp. 26–33).
  4. Hard quartzitic sandstones, the typical 'crowstones' of Staffordshire, are present in the south-west of the district.
  5. Potassium bentonite has been found to occur as thin bands of yellow, blue or orange clay or pyritous clay in the E2a and E2b zones in Edale by Trewin (1968, pp. 73–91). These are interpreted as altered bands of volcanic ash.

Following the discovery of shales of high radioactivity in the upper part of the E1a Zone in boreholes in the Castleton and Ashover areas (Ponsford 1955, pp. 31–3; Cosgrove in Ramsbottom, Rhys and Smith 1962, p. 164) a radiometric survey was made by Mr. J. Taylor on the Wardlow Mires outlier. This showed that a similar horizon showing high radioactivity was present close above the base of E1. At Ashover the high radioactivity was found to be linked with the presence of phosphatic fish remains and collophane which had absorbed the uranium. The horizon is that of the "Barren Beds" (E1a) of the Edale Borehole and the "Alport Crowstones" of the Alport Borehole, neither of which are exposed; however, the stratigraphical relationships of these beds have been since proved in the Wardlow Mires boreholes (see pp. 208–9).

The Edale Shales show the type of cyclic sedimentation described by Rams-bottom, Rhys and Smith in the Ashover area (1962, p. 114). The ideal cycle consists of a number of faunal phases: (11) Fish phase, (10) Planolites phase, (9) Lingula phase, (8) Mollusc spat phase, (7) Anthracoceras or Dimorphoceras phase, (6) Thick-shelled goniatite phase, (5) Anthracoceras or Dimorphoceras phase, (4) Mollusc spat phase, (3) Lingula phase, (2) Planolites phase, (1) Fish phase. These phases were considered to reflect variations in salinity. They bring out the otherwise indistinct cyclic nature of the shales of E, H and R age.

The extensive fossil collections of Hudson and Cotton in the Edale and Alport boreholes and neighbouring surface exposures (part of which have been donated to the Geological Survey) have been widely referred to in the present account, though some of the identifications have been revised. During the present work fossil collecting has been mainly aimed at filling such gaps as were found to exist in the Hudson and Cotton collections.

Evidence of the nature of the Namurian succession in the area of the 'block' is sparse, though the Wardlow Mires boreholes and the Hucklow Edge No. 1 Borehole show strongly condensed sequences at the base. Such condensed sequences appear to be restricted to slightly down-warped areas on the limestone surface.

Such elastic material as entered the area during the deposition of the Edale Shales has been considered by Holdsworth (1963) to have been introduced by northward-flowing turbidity currents bringing material from the south Midland landmass known, among other names, as the "Midland Barrier" (Trueman 1947, p. lxxx). The parent rocks were considered to have been greatly leached by weathering. The coarser true 'crowstones' were considered by Holdsworth to have been formed nearer the source of supply than the finer-grained and distal "Alport Crowstones".

Cravenoceras leion Zone (E1a)

The beds of this zone are known within the present district from boreholes only, as in most places they are overlapped by higher beds in the vicinity of the limestone massif. In the Castleton area their small outcrop is concealed beneath drift, while in the Wardlow Mires outlier they are present, though in condensed form.

Revision of the zonal boundaries (see p. 188) has caused more beds to fall within this zone than had previously been the case. The thickness varies considerably, from 436 ft in the Alport Borehole to 2 ft 1 inch in the Hucklow Edge No. 1 Borehole. The zone may be subdivided as follows:

(a) A lower and more uniformly developed part is made up of the beds with Cravenoceras leion Bisat at the base. These are shales with some thin limestones in places. In the Edale Borehole these beds are 73 ft thick with the C. leion fauna in the lowest 20 ft; a 6-ft bed with limestone pebbles occurs near the base, indicative of the contemporaneous erosion of the nearby limestone massif. Elsewhere, these beds are 45 ft in the Alport Borehole, 10 ft 7 inches in the Castleton Borehole and only 7 inches in the Hucklow Edge No. 1 Borehole.

(b) An upper poorly fossiliferous variable group of shales including the "Barren Beds" of the Edale Borehole (175 ft thick) and the "Alport Crowstones" of the Alport Borehole (391 ft thick). These beds are silty shales, with thin quartzitic siltstones. In the vicinity of the limestone massif they thin greatly and tend to lose their silty character; in the Hucklow Edge No. 1 Borehole they are only 1 ft 6 in thick. Plant and fish debris are the most important organic remains, though a sparse goniatite-bivalve fauna does occur (see p. 206). I.P.S.

The fauna of this zone in the Alport Borehole was discussed by Bisat (1950) who recognized representatives of all three subzonal faunas, though Eumorphoceras tornquisti (Woltersdorf) itself was not seen in the lowest of them. The middle fauna (E. stubblefieldi Subzone) includes Lyrogoniatites tonksi (Moore), Eumorphoceras bisati Horn (= E. pseudobilingue A Bisat) and C. leion. Yates (1962, p. 414) lists E. medusa Yates (recorded by Bisat 1950 as E. aff. hudsoni Gill) and E. medusa cf. sinuosum Yates in the upper fauna of the zone in the Alport Borehole. In the other boreholes circumstances have precluded detailed discrimination of horizons in E1a, though the E. tornquisti Subzone is known in the Edale Borehole.

An example of the rare fish tooth Edestus (Edestodus) was collected near the top of the zone in the Castleton Borehole. Among the bivalves, Posidonia corrugata (Etheridge) occurs throughout the zone, Caneyella membranacea (McCoy) and Obliquipecten costatus Yates near the base only, and P. trapezoedra (Ruprecht) in the upper part only. W.H.C.R.

Eumorphoceras pseudobilingue Zone (E1b)

Beds of this age are known mainly from boreholes, though they also appear in a small outcrop in the centre of the Edale Anticline (see (Plate 16A)); they also crop out at Castleton though here are beneath the drift. They consist of shales, silty in places and with some thin limestones. The latter are best developed at Edale where the uppermost 29 ft of the zone, here 34 ft in all, are exposed. The zone is subject to only minor variations in thickness in the area bordering the limestone massif, being 33.5 ft and 27 ft in the Castleton and Hope Cement Works boreholes respectively. At Mam Tor, however, it must be subject to even more rapid overlap than E1d (seep. 201). In the thick succession proved in the Alport Borehole these beds, 130 ft thick, are shales, silty in part and with scattered thin limestones. In contrast to this, in the condensed sequence proved by the Hucklow Edge No. 1 Borehole, the zone is only 4 ft in thickness. I.P.S.

The principal goniatite horizon contains E. pseudobilingue (Bisat) and the reported occurrence of Cravenoceras in this zone in the Alport Borehole (Hudson and Cotton 1943, p. 168) has not been confirmed. Yates (1962, pp. 414–5) comments on the absence in the Alport Borehole of E. angustum Moore which occurs in Ireland immediately below the horizon of E. pseudobilingue associated with a Kazakhoceras ? with nodose venter. This last-named was found just below E. pseudobilingue in the Castleton Borehole, and a similar form occurs in the Hope Borehole. E. pseudobilingue C Bisat characterized by early dying away of the transverse ribs was found just above the horizon of E. pseudobilingue s.s. in the Castleton Borehole in a position similar to that recorded by Yates (1962, p. 380) and is also known to the south in the Calow Borehole (see Smith and others 1967, p. 65). P. corrugata and P. trapezoedra are the commonest bivalves.

Above the E. pseudobilingue C horizon bivalves and Dimorphoceratids occur up to the overlying C. malhamense Zone. W.H.C.R.

Cravenoceras malhamense Zone (E1c)

The beds of this zone are known at outcrop only around the core of the Edale Anticline. They were also proved in the Castleton, Hope and Alport boreholes.

In the Edale valley the zone consists of some 50 ft of shale with about 20 ft of shales with thin limestones and siltstones in the middle. The uppermost part of the Castleton Borehole showed 14.5 ft of beds of this zone, though it is not certain whether the whole thickness was present. The Hope Cement Works Borehole proved a thick development; the lower beds with the C. malhamense fauna were dark calcareous shales with some thin limestone bands 16 ft thick, and these were overlain by 70 ft of dark shales with fish debris. The Alport Borehole showed 27 ft of shale with thin calcareous siltstone bands on 30 ft of shale with thin limestones with the C. malhamense fauna. The development in the Hope Cement Works Borehole is exceptional in that the zone is thicker here than in the Alport Borehole. In the Hucklow Edge No. 1 Borehole the zone is represented by 1 ft 4 in of mudstone and in the Wardlow Mires No. 1 Borehole by 10 in of mudstone; neither yielded a diagnostic fauna. I.P.S.

The characteristic goniatite fauna includes C. malhamense (Bisat) and Kazakhoceras scaliger (Schmidt), together with indeterminate Dimorphoceratids. Characteristic species other than goniatites are Caneyella membranacea and Posidonia corrugata. A nautiloid, Rayonnoceras sp., was collected from the Castleton Borehole, and the Alport Borehole yielded Reticycloceras sp., Actinopteria sp., fragmentary orthotetoids and productoids and the crustacean Ceratiocaris. W.H.C.R.

Eumorphoceras bisulcatum Zone (E2a)

This zone is known from surface exposures in the Edale valley and in the Wardlow Mires outlier and from the Hope Cement Works and Alport boreholes. Along much of the limestone–shale junction it rests unconformably on the limestone, as between Eyam and Bradwell and at Perryfoot. Along the western edge of the massif between Dove Holes and Buxton (One-inch Sheet 111) beds of E2a or later E2 age rest on the limestone. In the basin the thickness varies from about 80 ft in the Edale valley to 116 ft in the Alport Borehole. The sections at both localities show a development of beds with thin limestones in the lower part of the zone. The C. cowlingense Subzone at the base is some 40 to 45 ft in thickness at Edale and 68 ft in the Alport Borehole. The higher shales are somewhat silty in the Edale valley and pyritous with thin calcareous siltstones in the Alport Borehole. In the condensed sequence over the limestone massif a typical section of the zone is provided by Hucklow Edge No. 1 Borehole which proved a thickness of 20 ft 4 in with the C. cowlingense Band at the base and the E. bisulcatum Band at 6 ft 9 in above the base.

Recent work by Trewin (1968, pp. 76–8) has shown the presence of five thin bands of potassium bentonite in the upper part of the E. bisulcatum Subzone at Edale; these are mostly 1 cm or less in thickness though one band, near the top of the subzone, reaches 4 cm (see also p. 164). The bands have also been recognized in north Staffordshire. I.P.S.

Three levels in the zone yield a goniatite fauna. In the C. cowlingense Subzone at the base (which was referred to as E1d by Hudson and Cotton 1943) C. cowlingense Bisat occurs with poorly preserved Eumorphoceras bisulcatum. The main faunal horizon at the base of the succeeding subzone contains E. bisulcatum of which both Yates's subspecies erinense and ferrimontanum are found, Kazakhoceras scaliger, rare Cravenoceras sp., Chaenocardiola footii (Bally), Dunbarella sp. and crinoid debris. This fauna agrees closely with that found at the same horizon at Slieve Anierin, Co. Leitrim (Yates 1962) and elsewhere. Higher in E2a in the Alport Borehole there is another horizon containing E. bisulcatum s.l. at a depth of 367 to 371 ft (Hudson and Cotton 1943, p. 163), but the specimens are badly preserved and the band has not been recognized elsewhere. W.H.C.R.

Cravenoceratoides nitidus Zone (E2b)

Beds of this zone are exposed in the Edale valley, at Mam Tor, and were proved in the Hope Cement Works and Alport boreholes.

The thickness is about 60 ft in the Edale valley and in the Hope Cement Works Borehole and 65 ft in the Alport Borehole. In the Edale valley the succession may be summarized:

feet

(c) Shale, ferruginous in places

12

(b) Shale, with thin cherty limestones and silicified mudstones containing the Cravenoceratoides nititoides (Bisat) fauna including brachiopods and trilobites, mainly in a thin band near the middle

3

(a) Shale, with several goniatite horizons (see below); Cravenoceratoides edalensis (Bisat) at base

about 40–45

Near Mam Tor beds of this zone are considered by Hudson and Cotton (1945, p. 13) to rest directly on the Carboniferous Limestone. The Hope Cement Works Borehole yielded Cravenoceratoides nititoides near the top of 51 ft of shales referred to the E2b Zone. The Alport Borehole succession is generally similar to that in the Edale valley.

Trewin (ibid., p. 78, 80) has recognized the presence of a thin band of potassium bentonite near the base of the zone at Edale; the band has also been found in north Staffordshire. I.P.S.

The basal faunal band of E2b, that of Ct. edalensis, was first described (Bisat 1932) from the River Noe, near Skinner's Hall. The immediately succeeding faunas are not well known in the Edale valley though C. subplicatum Bisat and Ct. bisati Hudson were recorded in the Noe by Hudson and Cotton (1945, p. 9). The succession given by Hudson (1944, p. 241) is now subject to correction through increased knowledge of the succession elsewhere (summarized by Yates 1962, pp. 420–2). No examples of Ct. nitidus (Phillips) or its associated fauna are known from the Edale valley or from the Alport Borehole. Records of C. cf. nitidus by Hudson (1944) and Hudson and Cotton (1945) in the Edale valley and of the Ct. nitidus band in the Alport Borehole (Hudson and Cotton 1943) are now known to refer to Ct. nititoides. The next highest faunal band collected during the present work was that of C. holmesi Bisat which in the River Noe is found some 9 to 10 ft below the thin cherty limestone containing the Ct. nititoides fauna, which also includes crinoid debris, Productus hibernicus Muir-Wood, Eumorphoceras rostratum Yates, Weberides sp. and other fossils. This is one of the most persistent faunal bands in E2 (see Ramsbottom, Rhys and Smith 1962, p. 131). It should be noted that the fauna reported by Hudson and Cotton (1945) to contain Ct. nititoides has been re-determined as the lowest of the three N. nuculum horizons (ibid., p. 130).

Three sections show the relationship between the Ct. nititoides band and the overlying band containing N. stellarum (Bisat) and its associated fauna some 6 to 12 ft above (see below). W.H.C.R.

Nuculoceras nuculum Zone (E2c)

As re-defined by Holdsworth (1965, p. 229) this zone now includes (a) the N. stellarum Subzone, formerly included in E2b, and (b) the N. nuculum Subzone (corresponding to the former limits of E2c).

Beds of this zone are well exposed in the Edale valley and are also seen in smaller exposures at Mam Tor (though here in slipped material), at Perryfoot and at Dove Holes. The only complete section is provided by the Alport Borehole. They also appear in the axial region of the Todd Brook Anticline, near Saltersford.

In the Edale valley the zone consists of 45 to 60 ft of shale, with the N. nuculum fauna (see below) known mainly from a band 15 ft from the base. The Alport Borehole shows 89 ft of shale with thin bands of hard calcareous siltstone; the N. stellarum fauna occurs in a thin band at the base and the N. nuculum fauna in three bands, respectively 42 ft, 64 ft, and 73 ft above the base.

At Dove Holes the railway-cutting section, near the limestone boundary, shows 32 ft of beds of this zone beneath beds of H1 age. N. nuculum Bisat and E. bisulcatum occur in a band about 14 ft from the top. This suggests that the section finished just above the horizon of the middle band with N. nuculum proved in the Alport Borehole. If this is the case, the zone has, compared with the Edale valley, expanded a little in the vicinity of the boundary of the limestone massif.

The development of beds ascribed to E2c in the Todd Brook Anticline resembles that of the Staffordshire region (see Evans and others 1968, p. 33) in that thick quartzitic sandstones of 'crowstone' type occur throughout a thickness of some 200 ft of shales. These overlie about 50 ft of shale with, at one place, N. nuculum. I.P.S.

The Nuculoceras stellarum fauna at the base of the zone is also characterized by the presence of Posidoniella aff. vetusta (J. de C. Sowerby). The relationship between this fauna and the underlying Cravenoceratoides nititoides fauna is seen at the important Skinner's Hall section in the River Noe and in the outcrop near the confluence of the Noe and Crowden Brook. The N. stellarum fauna was also recognized in the Alport Borehole (Hudson and Cotton 1945, pp. 161–2).

Three horizons in the Alport Borehole are now known to contain N. nuculum and these correspond to the three such levels known elsewhere. The lowest of these seems always to have a poorer fauna than the two higher. Besides N. nuculum, the fauna of the zone includes Eumorphoceras bisulcatum [poorly preserved examples of two forms, one with less than 30 ribs per whorl and one with about 39 ribs per whorl], Ct. fragilis (Bisat) and bivalves. This zone marks the highest occurrence of Posidonia corrugata.

Homoceras subglobosum Zone (H1a)

This is represented in the Edale valley by about 30 ft of shale with beds of bullions at some levels. H. subglobosum Bisat occurs in a band with bullions at the base and, at least in places, at two higher horizons. In the Alport Borehole the zone is only 10 ft in thickness; it is thus the most variable part of H. I.P.S.

In addition to H. subglobosum, this zone includes Aviculopecten sp. (= Pterinopecten rhythmica Demanet 1943 non Jackson) and Posidoniella aff. variabilis Hind. Near the top of the zone in the Alport Borehole a band contains Homoceras sp. nov.with widely spaced trough-like striae and a well-developed lingua (Ramsbottom, Rhys and Smith 1962, p. 128, pl. 6, fig. 11). W.H.C.R.

Homoceras beyrichianum Zone (H1b)

In the Edale valley these beds show similar lithological characters to H1a, though there is a lesser development of bullions. The shales, some 50 ft thick, are sparsely fossiliferous, with H. beyrichianum (Haug). In the Alport Borehole the zone comprised 57 ft of mainly unfossiliferous shale, with H. beyrichianum in the lowest 6 ft. I.P.S.

The fauna was confirmed in an exposure at Fulwood Holmes only. Here, in addition to H. beyrichianum, it included Aviculopecten sp., Reticycloceras sp. and Posidoniella sp. The record from the Edale valley is on the authority of Hudson and Cotton (1945, pp. 6–7). Fossil collecting from the Alport Borehole was not detailed enough to reveal more than one horizon containing H. beyrichianum, but in the Ashover boreholes three such horizons were recognized (Ramsbottom, Rhys and Smith 1962, p. 128) which contain variants similar to those found in the Alport Borehole. It is therefore possible that these three horizons are actually present in this borehole. W.H.C.R.

Hudsonoceras proteus (H2a), Homoceras undulatum (H2b) and Homoceratoides prereticulatus (H2c) zones

In much of the Edale valley and in the Alport Borehole these zones comprise some 30 ft of shale with bands of bullions. At Upper Booth they expand to 40 ft. I.P.S.

At the base is the persistent band containing Hd. proteus (Brown) which also includes Homoceras smithii (Brown) towards the top. Higher up are successive goniatite horizons with Homoceras undulatum (Brown), H. eostriolatum Bisat and Ht. prereticulatus Bisat (see Hodson 1957). Caneyella semisulcata (Hind) and Posidoniella sp. are the characteristic bivalves. W.H.C.R.

Reticuloceras circumplicatile Zone (R1a) (formerly called R. inconstans Zone)

In the Edale valley this zone maintains a rather uniform thickness of 70 to 80 ft and consists of shale with some silty bands and thin ironstones. In the Alport and Ashop valleys it is thinner, Hudson and Cotton (1943, p. 164) recording some 45 ft of beds which now fall within R1a. I.P.S.

The lower limit of the zone is defined at the base of the band containing Homoceras magistrorum Hodson. Slightly higher, H. henkei Schmidt and Homoceratoides varicatus Schmidt occur. Specimens of Reticuloceras in this zone fall into two main groups: (a) Evolute forms with strong umbilical plications such as R. circumplicatile (Foord) and R. paucicrenulatum Bisat and Hudson and (b) Relatively involute forms with fine transverse ornament such as R. todmordenense Bisat, R. pulchellum (Foord) and R. subreticulatum (Foord). Members of these two groups are often found together; R. circumplicatile and R. pulchellum occur in the lower part of the zone; R. paucicrenulatum and R. todmordenense near the top. R. adpressum Bisat and Hudson is found at the top of the zone. The associated fauna includes species of Caneyella and Posidonia, with Dunbarella only in the upper part. W.H.C.R.

Reticuloceras nodosum Zone (R1b) (formerly called R. eoreticulatum Zone)

This zone is some 40 to 70 ft thick in the Edale valley and is, except for being slightly more silty, lithologically similar to R1a. In the Alport and Ashop valleys it is about 80 ft (Hudson and Cotton 1943, p. 164). At least 56 ft of the zone are exposed in the landslip-scar at Mam Tor.

At the western end of the Edale valley the zone is locally thin, R. nodosum Bisat and Hudson occurring only 34 ft below the base of the Mam Tor Beds; this is accounted for by a downward extension of the Mam Tor facies, possibly into the higher beds of R1b. This contrasts with the tendency, noted below in R1c immediately to the south (see p. 171). I.P.S.

R. dubium Bisat and Hudson, an almost non-crenulate finely ornamented derivative of R. adpressum, characterizes the lowest beds of the zone. Higher beds yield members of the R. nodosum group in which the shell is usually moderately evolute with strong transverse striae which regularly bifurcate. Hudsonoceras ornatum (Foord and Crick) and species of Homoceratoides and Homoceras also occur in the higher part of the zone. The type specimens of R. nodosum, R. stubblefieldi Bisat and Hudson and H. spiraloides Bisat and Hudson are from the present district. W.H.C.R.

Reticuloceras reticulatum Zone (R1c)

Owing to the diachronous character of the base of the Mam Tor Beds the part of this zone falling within the Edale Shales varies considerably in thickness. Over much of the Edale valley a mere 10 to 20 ft of shale of R1c age underlie the Mam Tor Beds. This shale is silty with some thin sandstones, especially towards the top, and forms a transition to the overlying beds. A similar development is present in the Alport and Ashop valleys. At the western end of the Edale valley all but 15 ft of the zone falls within the Mam Tor Beds while only half a mile to the south, in White-moor Sitch, 80 ft of R1c are included in the Edale Shales. Similar conditions obtain near Hope, where some 70 ft of R1c shales underlie the Mam Tor Beds. A small faulted inlier is present near Hathersage.

In the south-east of the district, at Eyam, the general regional thinning in that direction is more than compensated for by the lateral passage of Mam Tot Beds into shale; thus about 135 ft of shale of R1 age here underlie the Shale Grit. I.P.S.

The main palaeontological feature of the zone is a band at the base with Reticuloceras reticulatum (Phillips), R. davisi (Foord and Crick), Homoceras striolatum (Phillips) and Homoceratoides sp. In places this horizon contains a benthonic fauna including crinoid debris, brachiopods and gastropods (Hudson and Cotton 1943, p. 153). W.H.C.R.

Mam Tor Beds

At the type locality (see (Plate 16B)) the Mam Tor Beds consist of an alternating sequence of sandstones, siltstones and shales, at least 450 ft thick, which were originally described by Jackson (1927, pp. 17–8) as 'Mam Tor Sandstones'. This name was found inappropriate during the present work when these beds were examined over a larger area as the sandstone element is often much less developed than at Mam Tor. For this reason the term 'Mam Tor Beds' has been introduced (Gaunt 1960, p. 32) as being less misleading than, though synonymous with, the older term.

The stratigraphical limits of the Mam Tor Beds vary in some degree owing to the diachronous nature of both base (see also p. 170) and top. The base is marked either by the incoming of sandstone beds of some importance (say over one foot in thickness and of reasonably frequent occurrence) or, in places where the sandstones are less developed, by a general upward increase in the arenaceous content of the shales. The upper limit, also, is diachronous as where thick sandstone bands of massive character develop about this horizon they are placed in the Shale Grit.

The Mam Tor Beds are present in the Edale, Alport, Ashop, Derwent, Perryfoot and Hope valleys and at Mam Tor. Their thickness varies from about 200 ft in the northern and eastern exposures (northern side of Edale valley, Ashop and Alport valleys and near Hathersage) to 450 ft at Mam Tor. In a south-westward direction they pass laterally into the lowest part of the Shale Grit. This is attributed to the deposition of the Mam Tor Beds of normal facies in a shallow-water environment adjacent to the massif where the winnowing action of currents removed the clay fraction. The mode of disappearance of the Mam Tor Beds to the south-east, however, is rather different; while the uppermost beds pass laterally into a sandstone which joins the Shale Grit, in a similar manner to that described above, the lower beds lose their identity near Brough owing to a general decrease in the arenaceous content, and pass laterally into shales which are no more than the normal thin sandy phase transitional to the Shale Grit.

The type section at Mam Tor has been the subject of a detailed study by Allen (1960, pp. 193–208), on which the following description is largely based. The exposed section of these beds, given by Allen as 350 ftThis appears to be under-estimated, the present estimate being 400 ft for the beds exposed in the face, with a further 50 ft of unexposed strata above. in thickness, is made up of a large number of cyclic units, the whole showing certain similarities to flysch deposits. The overall sedimentary pattern has affinities with the Edale Shales at the base, there being a marked shale component; towards the top the sandstone component is more important, indicating an approach to Shale Grit conditions.

The cyclic unit, which usually varies from 3 to 8 ft in thickness, is made up as follows:

The massive sandstones usually have a little feldspar (1.0 to 11.9 per cent), which is either orthoclase, microcline or albite (Allen 1960, p. 197). There are some mica- or siderite-rich bands. The laminated sandstones show similar mineralogy but are, as would be expected, commonly more micaceous ; they show low-angle cross-bedding and ripple-drift bedding (Sorby 1859) in many cases. The base of each sandstone is sharp and frequently shows sole-marks, the several types of which are summarized below. Graded bedding is another conspicuous feature. The massive sandstones often contain beds of shale conglomerate or breccia. The conglomerate fragments are the smaller (up to about 5 cm) but Allen (1960, p. 197) records fragments up to 75 cm diameter in the breccias. So far as the width of the section at Mam Tor (about 100 yd) is concerned, the sandstones show little lateral variation.

The siltstones, apart from their smaller grain-size, are generally similar to the laminated sandstones. The shales and mudstones, in the lower part of the Mam Tor Beds, closely resemble the Edale Shales, but tend to be more sandy in the higher part. The shales yield, in places and especially towards the base, a poor goniatite–bivalve fauna indicative of the R1c Zone. The chief forms are Reticuloceras cf. reticulatum, Homoceras sp., Homoceratoides sp. and Dimorphoceratids, together with Caneyella and Dunbarella. Carbonized wood debris is of fairly common occurrence in both sandstones and shales, and larger plant stems are sometimes present in the sandstones.

The undersides of the sandstones bear a variety of sole-markings, all described and several figured by Allen who also lists the literature on this subject. The most important of these structures are: (a) Flute casts; these are ridges with an abruptly raised end towards the source of the current which produced them, and tapering off in the opposite direction. Their orientation has been shown by Allen to be nearly due south, indicating currents flowing from the north. (b) Groove casts; these are linear structures attributed to the grooving of the underlying surface by objects, such as drifting wood fragments, dragged over it by the current. (c) Load-casts are unorientated lobate structures formed by the unequal loading of mud by coarser sediment. (d) Trail casts and burrows are cylindrical casts of marks left by organisms on the mud surface before the overlying sandstone was deposited.

Penecontemporaneous deformational (slump) structures, though not so typical of the Mam Tor Beds as sole-marks, are present locally. They include convolute bedding, corrugated bedding, crumpled bedding (Allen 1960, p. 202) and slump-balls. Some of the latter structures reach a diameter of 50 cm.

The present work, extending over a wide area, has shown the Mam Tor Beds to be much more variable than is apparent at Mam Tor. Only a mile to the east, at Brockett Booth, sandstones are much less frequent and are much thinner. Elsewhere relatively thick sandstones of mappable proportions are locally present.

The conditions of deposition have been discussed in detail by Allen, who states "that intermittent turbidity currents rapidly deposited the sandstones in a deep marine environment where clays were normally being slowly formed" (op. cit., p. 205). This is considered to have been at the distal end of the slopes fronting a large delta, lying to the north.

Shale Grit

The Shale Grit consists of a thick sequence of sandstones, often massive, with shale bands. The name (Farey 1811, p. 228) apparently derives from the presence of the shale bands or from the common occurrence of shale pellets in the sandstones. The Shale Grit forms a broad spread of moorland flanking Kinder Scout but showing nearly everywhere a less craggy topography than that formed by the Kinderscout Grit. In places, however, the lower or middle parts of the Shale Grit stand out as strong escarpments.

As in the case of the Mam Tor Beds, the limits of the Shale Grit are somewhat diachronous. The lower limit has already been discussed above. The practice here followed in the fixing of the upper limit has been to include in the Shale Grit all sandstones below the thick shale sequence ('Grindslow Shales', see p. 175) separating the Shale and Kinderscout grits. If the general relations of the shale partings and sandstones within the Shale Grit are considered, two types of development are apparent in the Chapel en le Frith district: (a) A regular development in the north around Kinder Scout extends eastwards to include the upper valley of the Derwent, Hathersage and Offerton Moor. Here the thickness varies from 700 ft near Hayfield and 600 ft in the Ashop valley and in the western end of the Edale valley to about 300 ft near Hathersage. The sandstones tend to be some 50 to 60 ft in thickness (though they are thicker where the shale partings fail locally) and the shale partings up to about 10 ft. Individual shale bands can be traced laterally for considerable distances. The lowest part of the Shale Grit shows a lesser development of massive sandstones than the overlying beds, their place being taken by alternating beds of 'Mara Tor' type. The middle part shows a marked development of thick, massive sandstones, which are in places coarse and pebbly; a thin ganister-like sandstone, with Stigmaria locally, is present at the top of this subdivision in the middle part of the Ashop valley.

The highest beds are to some extent transitional to the 'Grindsiow Shales' with two or more sandstones very regularly developed in the ground north-east of Kinder Scout. (b) A marginal development, in the south-western and southeastern outcrops, heralds the southern disappearance of the Shale Grit. Here the different sandstones are irregular, contrasting strongly with the regular development described above. The shales, for example, may coalesce, giving thick beds, up to 100 ft at Bagshaw and 60 ft at Abney; these beds are, however, of small lateral extent. In general, in the south-western outcrops the Shale Grit thins rapidly to the south and disappears a little north of Dove Holes. In the south-eastern outcrops, in addition to the southerly thinning there is a tendency for the shale partings to disappear towards and to some extent over the limestone massif giving a single sandstone at Eyam—the Eyam Edge Sandstone of Morris (1929, pp. 41, 58)—which is about 200 ft thick. This, however, dies out just south of the present district near Curbar.

Near the northern boundary of the district the Charlestown Borehole (see p. 211) was put down to a depth of 586 ft below the base of the Kinderscout Grit and failed to prove any Shale Grit. Since the intervening shales are only some 300 ft thick in outcrops a mile away, at least the uppermost 286 ft of the Shale Grit must have failed here. It is considered that the whole of the Shale Grit may be absent at this locality. The Shale Grit is normally developed, except for some increase in the shale partings, in the nearest outcrops.

The Shale Grit is also absent in the Todd Brook Anticline; it thus fails in a westerly direction in the Goyt Trough in addition to the southerly direction already noted around the Derbyshire Dome. The thick development at Hayfield, however, suggests the presence here of a concealed tongue of Shale Grit extending westwards into the Goyt Trough.

The sandstones of the Shale Grit are of medium to coarse grain, usually massive, with common included shale pellets and large load-casts on the under surfaces of beds. Ripple-marks have also been observed in many places. Very coarse sandstones, nearer in lithology to the Kinderscout Grit, occur locally near the top of the middle part of the Shale Grit. In a detailed consideration of the sedimentology of the Shale Grit in the Alport, Ashop and Derwent valleys, Walker (1966, p. 99) states that the coarser sandstones are in individual beds up to 10 ft thick and show scouring at their bases with downcutting to the extent of 3 to 4 ft. Groups of these sandstones may total 50 to 100 ft in thickness. The bases are sharp and in places show sole-marks, especially load-casts (up to 18 in diameter) and less commonly flute casts (up to 3 ft by 1 ft). He further recognizes beds of alternating type, comparable with the Mam Tor Beds; these show a variety of sole-markings. The argillaceous beds were divided by Walker (ibid., pp. 101–4) into silty mudstones, pebbly mudstones and thinly laminated black mudstones. The silty mudstones commonly contain thin interbedded sandstones, the pebbly mudstones frequently show slump structures, and the black mudstones recall the lithology of the fossiliferous marine strata in the Edale Shales but are usually barren.

Walker (ibid., pp. 95–101) attributed the deposition of all the arenaceous beds in the Shale Grit to the action of turbidity currents. The beds of Mam Tor' type, more frequent in the lower part of the Shale Grit, were interpreted as of distal origin (see p. 173) while the massive sandstones of less obvious 'turbidite' origin and more frequent in the upper part of the Shale Grit, were considered to be proximal, the delta front having advanced farther into the area. The thicker sandstones are regarded by Walker as 'turbidites' mainly on account of their sharp bases with sole-marks and lack of cross-bedding. This mode of origin accords well with the uniformity of the bedding and shale partings in the 'regular development' of the Shale Grit. The thick sandstone bands of 50 to 100 ft are considered by Walker to be of composite origin, the mud fraction having been winnowed out by current action.

Shales between Shale Grit and Kinderscout Grit

The Shale Grit is separated from the Kinderscout Grit by a series of shales and sandy shales with thin sandstones and siltstones and a few thicker sandstone bands. These beds, about 220 ft thick around Grindslow Knoll and Grinds Brook, have been called the "Grindslow Shales" by Jackson (1927, pp. 16–7), who noted their variability in thickness elsewhere. Farther east they are 120 to 150 ft thick, but thin somewhat to the south-east to 100 ft at Abney. The maximum development is north of the Kinder Scout plateau where 350 to 400 ft of shale are present; from here rapid thinning to the south-west occurs, only 30 ft being present in the lower reaches of the Kinder valley, near Hayfield. Still farther south the beds appear to expand, but this is partly due to lateral passage of the Lower Kinderscout Grit into shales. With the disappearance of the Shale Grit the group cannot be recognized beyond Dove Holes.

The lithology of the shales in the Alport, Ashop and Derwent valleys has been considered in detail by Walker (ibid., pp. 101–4) and the following types recognized mudstones (not falling in other groups), paper laminated mudstones (rare), sandy and silty mudstones with horizontal burrows, unbedded sandy and silty mudstones. The last two types are said by Walker to be restricted to the Grindslow Shales. The associated sandstones (ibid., pp. 104–5) are divided into parallel-bedded silty sandstones and parallel-bedded carbonaceous sandstones, the former being restricted to the Grindslow Shales as a whole and the latter restricted to their upper part.

Kinderscout Grit

The Kinderscout Grit is made up of one or more leaves of massive sandstone, typically coarse and commonly pebbly. The lithology contrasts strongly with that of the Shale Grit, but shows features in common with that of higher beds, particularly the Chatsworth Grit.

The Kinderscout Grit gives rise to many of the most striking topographical features in the district, particularly the plateau of Kinder Scout; here wind-eroded stack-like outcrops are frequent, the most striking being Crowden Tower and Noe Stool. Derwent Edge shows similar features such as the Wheel Stones and the Salt Cellar. Strong scarp features are also typical, good examples being Kinder Downfall (see (Plate 18A)), The Edge, Derwent Edge and Bamford Edge.

Except in the south-west and south-east of the district it has been possible to subdivide the Kinderscout Grit as follows:

This follows the usage in the Holmfirth and Glossop district (Bromehead and others 1933, p. 15). The two divisions of the Kinderscout Grit are not, however, named separately on the map. The recognition of the Butterly Marine Band as far south as Hayfield and Strines (near Bradfield) represents a considerable extension southwards of the known occurrences of this band.

(a) The Lower Kinderscout Grit

(a) The Lower Kinderscout Grit is coarse, feldspathic, massive and frequently pebbly. It is 300 ft thick on the west side of Kinder Scout and 250 ft at Hayfield. It thins rapidly northwards from Hayfield, being only 74.5 ft in the Charlestown Borehole. Traced southwards, it splits into a number of leaves which then die out, the upper ones failing first; the whole of the Lower Kinderscout Grit thus fails by the time Chapel en le Frith is reached.

To the east of the Derwent valley the Lower Kinderscout Grit is most fully developed around the head of Howden Dean where it consists of a 150-ft thick lower leaf and an 80-ft thick upper leaf, separated by about 120 ft of shales and siltstones. The lower leaf, a coarse pebbly massive sandstone where it forms the main escarpment north of Howden Dean, splits southwards into two beds, both of which thin and die out below Derwent Edge. The upper leaf expands southwards to between 120 and 180 ft of coarse pebbly massive sandstone where it forms the main escarpments of Derwent Edge and Bamford Edge. Large-scale current-bedding foresetting towards the south-west is conspicuous and results in anomalous oblique features running across and down the fronts of these edges. The Lower Kinderscout Grit thins appreciably southwards along Bamford Edge. To the north of Hathersage it unites locally with the Upper Kinderscout Grit. East and south of Hathersage a number of individual beds again become discernible, though they cannot be correlated with any certainty with the Upper and Lower Kinderscout grits.

The top surface of the Lower Kinderscout Grit is often ganister-like and sometimes bears Stigmaria.

(b) The shales with the Butterly Marine Band

The shales with the Butterly Marine Band vary on the western outcrops from 87 ft (in the Charlestown Borehole) to 33 ft. Some of this variation may be due to channelling at the base of the Upper Kinderscout Grit. The best section was provided by the Charlestown Borehole: this showed a thin coal and seatearth at the base, overlain by the Butterly Marine Band, here showing the remarkable thickness of 27 ft. The band has the typical benthonic mollusc and brachiopod fauna listed by Bromehead and others (1933, p. 145) and, in addition, a phase with Reticuloceras sp. nov.near the base. The upper part of the band showed two non-marine interdigitations with Cochlichnus kochi (Ludwig) and fish debris (see below). A thinner development of the band was found at Chunal and south-east of Hayfield and it probably dies out a short distance to the south of the latter place.

Near South Head, east of Chinley, the lateral passage of the upper part of the Lower Kinderscout Grit into shales results in an overall thickening of the overlying shales to some 350 ft. A dark carbonaceous mudstone towards the top of these shales may represent the horizon of the thin coal below the Butterly Marine Band in the Charlestown Borehole.

On the eastern outcrops these shales are some 70 ft thick. About three-quarters of a mile north of Foulstone Delph the Butterly Marine Band was found near the base as an 11-in band with Reticuloceras sp. and fish debris, the benthonic fauna being apparently absent here. At Bole Hill the shales disappear where the Upper and Lower Kinderscout grits unite. I.P.S.

The present district sees a transition in the fauna of the Butterly Marine Band. In the Holmfirth and Glossop (86) district to the north (Bromehead and others 1933, pp. 145–6) the fauna comprises largely benthonic forms such as Lingula mytilloides J. de C. Sowerby, Orbiculoidea nitida (Phillips), Retispira undata (Etheridge jun.), Sanguinolites ovalis Hind and S. tricostatus (Portlock) together with a few nectonic species such as Aviculopecten dorlodoti Delépine and extremely rare goniatites (only two specimens are known from the Glossop district despite intensive collecting). This type of fauna persists in the western part of the present district but goniatites are more common. In the Charlestown Borehole, where the band is some 27 ft thick, the basal 4 ft has a typical benthonic fauna without goniatites. From 4 to 5 ft above the base Lingula and S. ovalis occur with Reticuloceras sp. nov.Higher beds contain mainly Lingula and bivalves, but at two levels there are apparently non-marine interdigitations, the lower of which contains the sineoid trail Cochlichnus kochi and the upper fish debris only. Around Chunal the band is thinner and contains a benthonic fauna as well as Reticuloceras. To the east (see pp. 223–4) the fauna consists of Reticuloceras sp. nov.and fish debris only. Anthracoceras has not been collected anywhere at this horizon. W.H.C.R.

(c) The Upper Kinderscout Grit

The Upper Kinderscout Grit consists of sandstones, usually of medium grain, with some coarser bands and in places bands with shale pellets. The thickness varies in the western outcrops from about 60 to 150 ft, and in the eastern from 60 to 90 ft. At Chinley, borehole evidence (see p. 221) suggests the lateral passage of the top 40 ft or so of the Upper Kinderscout Grit into silty mudstones and siltstones: otherwise it is much less variable than the Lower Kinderscout Grit. On the main western outcrop the Upper Kinderscout Grit continues south of Chapel en le Frith to the southern edge of the district. On the eastern outcrops it joins with the Lower Kinderscout Grit at Bole Hill, as has already been noted.

The top of the Upper Kinderscout Grit is often ganister-like, bearing rootlets and Stigmaria. A thin seatearth, and in the north-east a thin coal, overlain by a small thickness of shale, is usually present between it and the Reticuloceras gracile Marine Band.

In the area where the Kinderscout Grit has not been subdivided it is developed as follows: (1) In the Todd Brook Anticline 180 ft of sandstone with subsidiary shale partings are present in the northern part; farther south it thickens to about 320 ft and a lower leaf appears, some 50 ft below the upper and 70 ft thick. No correlation of these leaves with Upper and Lower Kinderscout Grit is implied. (2) On the eastern side of the area, east and south of Hathersage, after the junction of Upper and Lower Kinderscout grits already noted, a shale parting appears again in approximately the position of the shale with the Butterly Marine Band. This splits the Kinderscout Grit, some 200 ft thick in all, into two approximately equal leaves between Hathersage and Grindleford. To the south of the latter place, thinning occurs and the Kinderscout Grit eventually dies out between Bakewell and Rowsley.

The conditions of deposition of the Kinderscout Grit were considered by Trotter (1952, pp. 78–9) who classed it as of "fluvial-grit facies". This was made up of massive spreads of grit "of the valley-spread type and possibly of the piedmont type". The Kinderscout Grit is now generally accepted as of fluviatile origin (see, for example, Holdsworth 1963, p. 135; Collinson and Walker 1967, pp. 80, 87–8) and the orientation of the current-bedding indicates a northern or north-easterly source. The petrography also falls into line with this conclusion, the sandstones being coarse arkoses of the type described farther north in the west and north Yorkshire area by Gilligan (1920, pp. 253–75) and shown by him to have been derived from the denudation of an area of crystalline rocks lying to the north-east.

After the deposition of the Lower Kinderscout Grit it is evident that more regular conditions favouring cyclic sedimentation were established (Reading 1964, p. 345). These conditions continued during the deposition of most of the higher part of the Millstone Grit in the north Derbyshire area.

Middle Grit Group (Marsdenian, R2)

The Middle Grit Group extends from the base of the Reticuloceras gracile Marine Band to the base of the Gastrioceras cancellatum Marine Band (see (Plate 19)). In contrast to most of the Millstone Grit so far described, this succession shows clear-cut widely traceable cyclothems, there being six or seven present over most of the district and eight where the Reticuloceras superbilingue and Donetzoceras sigma bands are so split as to lie in different cyclothems. Several of these cyclothems are, however, incomplete, and in certain parts of the group there is considerable lateral variation.

Beds between Kinderscout Grit and Chatsworth Grit

These beds show great variation in thickness. In the western outcrops they range from 550 ft near Glossop to 1500 ft south of Kettleshulme. This southerly thickening is not, however, so acute near the limestone massif, the thickness near Dove Holes being only about 900 ft. The eastern outcrops show the southerly thinning usual on that flank of the Pennines, from some 400 ft between Bradfield and Stanage to 250 ft south of Hathersage. The thickness variations are at least in part accounted for by the incoming or disappearance of sandstones.

Western area

The lowest 80 to 100 ft of these beds are the least variable and show a fairly uniform development of four marine bands whose fauna is discussed on p. 183:

(a)    The Reticuloceras gracile Marine Band, usually from 4 to 5 ft thick, is a persistent feature at the base. It is typically grey platy shale with R. gracile Bisat and other fossils.

(b)   The R. bilingue early form Marine Band, from about 2.5 to 7 ft thick, consists usually of dark calcareous shale, locally pyritous. It lies from 14 to 30 ft above the R. gracile Band.

(c)    The R. bilingue Marine Band lies approximately half way between the bands with R. bilingue early form and R. bilingue late form. Its thickness varies from 7 in to 7 ft. The thinner developments are usually made up of dark calcareous shale, but in the thicker ones the marine fauna extends upwards into the overlying grey shales.

(d)   The R. bilingue late form Marine Band, lying at the top of the group, is usually some 3 to 5 ft thick. The lithology varies from dark 'sulphurous' shale to dark slightly silty shale.

The following exceptional thicknesses in this district of the three lowest of these bands were proved in a borehole at Whitehough: R. gracile 18 ft 10 in, R. bilingue early form 14 ft 9 in and R. bilingue 14 ft 8 in.

The relationships of the above beds are illustrated in (Plate 19). Between the R. bilingue late form horizon and the R. superbilingue horizon the great variability contrasts strongly with the regularity of the beds below. The thickness of this group of strata varies from as little as 50 ft at Chunal to 1000 ft in the Todd Brook Anticline. The belt of thick sedimentation between these horizons extends southwards and also south-westwards into the Macclesfield area (Evans and others 1968, p. 57). The most important feature associated with this thickening is the incoming of the Corbar and Roaches grits, which together are equivalent to the Ashover Grit of the country to the east (Smith and others 1967, p. 60). The Corbar Grit is the least extensively developed, though it is present in the south-western part of the district where the Roaches Grit fails. It is in general fine-grained and flaggy and reaches a thickness of 300 ft in the Todd Brook Anticline, south of Kettleshulme (Plate 19), dying out northwards. At Corbar Hill, in the Buxton (111) district to the south, it lies close beneath the Roaches Grit, giving rise to a composite sandstone group 600 ft thick. To the north-east of Corbar Hill the grit rapidly dies out, but its place is taken by a group of silty or sandy shales with thin siltstones or sandstones. The Roaches Grit, separated from the Corbar Grit by some 250 ft of shale in the Todd Brook Anticline, is more extensively developed. It makes its appearance at Chinley and thickens southwards. It is very variable in development with a marked tendency for different leaves to split or to unite. The lithology varies from coarse and massive to fine-grained and flaggy. Some beds bear large sole-marks, mainly load-casts. The coarser massive developments recall the 'fluvial grit' facies (see p. 162), while the finer are comparable to the Shale Grit.

The Reticuloceras superbilingue Marine Band is separated from the Roaches Grit, in the present area, by from 30 to 200 ft of shale; typically, in the southern part of the Goyt Trough, the marine band lies directly on the grit (see Cope 1946, p. 142). At Chunal the marine band consists of 2 ft 4 in of dark shale. In the vicinity of Combs Moss, however, it is usually represented by only a few inches of hard calcareous flags.

The R. superbilingue Marine Band is overlain by shales some 300 to 350 ft thick. Apart from the local occurrence of the Donetzoceras sigma Band these beds call for little comment, except to note the presence in them of several impersistent sandstones north of Chinley.

In the western outcrops the Donetzoceras sigma Marine Band is known only near Hayfield where it is 4 in thick. Judging from the eastern outcrops (see below) and from the position of the band at Oakenclough, in the Macclesfield (110) district (Evans and others 1968, p. 63), it would appear to lie about 40 to 50 ft above the R. superbilingue Band, though this interval cannot be directly determined in the present area.

Eastern area

The succession here is thinner than in the west, the thickness being 400 ft in the north around Strines Moor and about 300 ft below Millstone Edge. The general succession is the same as in the west, though the R. bilingue early form Marine Band appears to be absent and in the north-east of the district the Heyden Rock is present beneath the R. bilingue late form Marine Band (see Eden and others 1957, p. 19).

The Heyden Rock is present between Bradfield Moors and Moscar House, but then dies out rapidly southwards. It is usually medium-grained in texture, but locally becomes coarser and pebbly. The thickness is about 80 ft at Bradfield. The Heyden Rock is more extensively developed in the Holmfirth and Glossop district where it was mistakenly correlated with the Rivelin Grit (Edwards 1932, pp. 180–1), a mistake rectified by Davies (1941, pp. 241–4). In the present district, a temporary section on Strines Moor (see p. 232), showed the unusual feature of a 3-in band of sandstone with abundant casts and moulds of Carbonicola just below an 11-ft shale parting towards the top of the Heyden Rock. This is the lowest record of Carbonicola in the Pennine province.

The shales above the R. bilingue late form Marine Band, some 200 ft thick, contain a better development of the R. superbilingue and D. sigma marine bands than in the western outcrops. The R. superbilingue Marine Band lies about 100 ft above the R. bilingue late form Band, and in the south-eastern corner of the area overlies the Ashover Grit which comes in to the south and is fully developed in the Chesterfield district (Smith and others 1967, p. 60). The R. superbilingue and D. sigma bands are about 30 to 50 ft apart.

The R. superbilingue Marine Band is usually hard and platy shale or dark 'sulphurous' shale from 1.5 to 2 ft in thickness. Near Sugworth it is possible that the band expands, the fauna extending over as much as 30 ft of shale. A thick development of the band was present near Sheffield in the Hallam Head Borehole (Davies 1941, pp. 241–2) where the fauna ranged through at least 16 ft and the bottom was possibly not proved.

The Donetzoceras sigma Band is typically composed of two leaves, each about 3 in thick and 5 ft apart. The upper seems always to contain the D. sigma fauna while the lower commonly contains Lingula only. At Jacob Plantation, Sugworth, the D. sigma fauna ranges over 8 ft of shale; as in the case of the R. superbilingue Band this may be compared with the Hallam Head Borehole where the fauna was present "at certain horizons" (Davies 1941, p. 242) over 15 ft of shale.

Near Grindleford both R. superbilingue Bisat and D. sigma (Wright) are present in some abundance in both bands.

Source of the Roaches, Corbar and Ashover grits

The northward disappearance of the Roaches and Corbar grits in the west and the Ashover Grit in the east contrasts strongly with the behaviour of other grits, such as the Kinderscout Grit, which die out towards the south. The Roaches Grit is coarse and pebbly at the type locality (Challinor 1921, p. 81) but becomes finer grained in general northwards; in the Chesterfield district Smith and others (1967, p. 68) also noted that the Ashover Grit is coarsest in the south and becomes finer grained northwards. These facts alone suggest that the two grits were derived from the south, and this is further supported by the northward orientation of the foresetbeddingSee Stephens, E. A. 1952, pp. 224–5, though the Ashover Grit is here mistakenly called the 'Upper Kinderscout Grit' (Smith and others 1967, p. 71).. The outcrops of the Roaches Grit show both a coarse development comparable with the 'fluvial-grit' facies and a finer-grained facies with shale partings which is in many respects comparable to the Shale Grit. These can be attributed respectively to the upper surface and frontal slopes of a delta advancing into the area from the south.

Chatsworth Grit

With the exception of the Rough Rock, the Chatsworth Grit forms the most constant sandstone horizon in the Millstone Grit of the region; moreover, the sandstone, or its equivalent the Huddersfield White Rock, occurs over most of the south Yorkshire and Derbyshire area. For these reasons it has been possible to abandon such local names as Rivelin Grit, current in the Sheffield area (Eden and others 1957, pp. 14, 18), or Shining Tor Grit, put forward by Cope (1946, p. 142) in the Goyt Trough, in favour of the more widely used term 'Chatsworth Grit'.

The Chatsworth Grit shows marked variations both in lithology and thickness. Two main lithological types may be recognized:

A fine-grained lithofacies occurs north of a line from Kettleshulme, through Chinley Churn to Moscar. The Chatsworth Grit is here a coarse- to medium-grained sandstone, yellow-brown in colour, and up to about 80 ft thick. Near the southern limit of this facies it frequently thins to as little as 25 ft (Bradfield Dale) and 43 ft (Grove Mill Borehole, New Mills) and at Kettleshulme it is apparently split, thin and ill defined, though here there is some complication due to faulting. Near Hayfield it is split into two leaves and to the west of Chunal, although the split is not apparent, its position is marked by a ganister. In the north-east of the area, near Bradfield, the Chatsworth Grit is also split.

Over the remainder of its outcrop the Chatsworth Grit is very coarse, pebbly, massive and feldspathic; it is usually cross-bedded in a general southerly direction, though in the east this changes to south-west or west. These lithological characters have much in common with those of the Kinderscout Grit. The thickness is usually about 100 ft, but reaches 150 ft locally in the Goyt Trough, where the grit shows marked red staining in most exposures and the associated mudstone partings near the base are also deeply stained (see p. 235). The eastern exposures show no red staining, the colour of the rock being yellow-brown, though otherwise the lithology is similar to that of the reddened rock. An impersistent lower leaf, some 40 to 60 ft thick, is present beneath the main bed around Hathersage.

The coarse facies of the Chatsworth Grit forms marked features, such as Combs Moss and Eccles Pike on the west and Stanage Edge, Higger Tor, Froggatt Edge and Curbar Edge on the east. Around Hathersage millstones were, until recent years, produced from the Chatsworth Grit.

The top of the Chatsworth Grit is usually either ganister-like or a true ganister, and is overlain by the Ringinglow Coal or its seatearth.

The red coloration of the Chatsworth Grit in the western outcrops is a striking feature largely restricted to the coarse facies in which it is almost ubiquitous. Associated finer sediments such as flaggy sandstones and siltstones at the base are deeply stained, and associated mudstone partings even more so. Thin sections (see p. 260) show the reddening to be subsequent to both sedimentation and diagenesis as the hematite lies outside secondary quartz overgrowths. It seems likely that the coarse sandstones were particularly favourable to the transmission of reddening solutions during or just before the Permo-Trias.

Beds between Chatsworth Grit and Gastrioceras cancellatum Marine Band

These beds, which include two complete cyclothems above the Ringinglow Coal, vary somewhat in the present district, the average thickness on the east being about 120 ft, while on the west it is only some 60 ft.

Western area

These beds are usually about 55 to 60 ft thick, but on the western side of Eccles Pike they reach 100 ft and represent a westward extension of the thick sedimentation of the eastern area (see below).

At the base, the Ringinglow Coal and its seatearth normally lie on top of the Chatsworth Grit. The coal varies between 10 and 19 inches in most places south of New Mills, but on Wild Moor, near the southern edge of the district, it thickens to 23 in. To the north of New Mills the coal is frequently thin or absent. It is usually underlain by 1.5 to 2 ft of seatearth, but locally, west of Whaley Bridge, it rests on 8 in of ganister. Near Hayfield (see p. 236) a 3-ft ganister occurs a little below the horizon of the Ringinglow Coal and is separated from it by a few feet of sandstone.

In the north, at Simmondley, the beds between the Ringinglow and Simmondley coals are about 40 ft thick and consist entirely of shale. They are not well exposed between Rowarth and Chinley but to the south they show rather constant characters in the Goyt Trough and Todd Brook Anticline. Here the thickness is usually about 25 ft, the upper part, and in many places the lower, being sandstone, though this fails around the nose of the Todd Brook Anticline. In Fernilee No. 1 Borehole the top 17 ft were sandstone and yielded Naiadites sp. in a 1-ft mudstone parting near their base.

The Simmondley Coal reaches its greatest thickness, 24 to 30 in, at the type locality near Glossop where it has also been called the 'Two Sheds'. Farther south information regarding the seam is scanty as far as Whaley Bridge, but it is better known south of that place. In Fernilee No. 1 Borehole the coal was 24 in thick but included an 8-in mudstone parting. Around Errwood the thickness was 15 in; the coal was of better quality here and was worked under the name 'Little Mine'.

A variable thickness of shales separates the Simmondley Coal from the G. cancellatum Marine Band. These beds are probably only a few feet in thickness near Glossop. In the Goyt Trough, south of Whaley Bridge, they are usually about 20 ft, but they thin again southwards to under 9 ft near Errwood. Between Whaley Bridge and Eccles Pike a sandstone in the position of the Redmires Flags is present in this group of strata. The Fernilee No. 1 Borehole proved the unusual thickness of 32.25 ft, the lowest 2.5 ft being dark carbonaceous mudstone with Curvirimula belgica (Hind); this was overlain by 7 ft 8 in of mudstone with Planolites sp., Anthracoceras sp., a productoid and Sanguinolites sp. ; the uppermost beds were shales, locally pyritous. This marine band has not been located in surface exposures in the vicinity, and its presence seems to be related to the local thickening of this part of the succession. A Lingula band is present at this horizon at several places on the eastern side of the district and in the adjacent Sheffield area.

Eastern area

The thickness of these beds varies from 120 ft at Bradfield to 140 ft near Brown Edge. The Ringinglow Coal at the base varies from 12 in to 24 inches in thickness. It is succeeded by 90 to 100 ft of shales. The Lingula band above the coal is exposed in Oaking Gough; the band is better developed in the adjacent Sheffield area (Eden and others 1957, pp. 20–1). The Simmondley Coal is not known, owing to lack of exposures; it is, however, sporadically developed in the adjacent Sheffield area, for example in the Rod Moor No. 3 Borehole (ibid., p. 20) where it was 21 in thick. Sandy mudstones and sandstones between the two coals have been called the "Brown Edge Flags" by Pulfrey (1934, p. 259), but the name is invalidated by the fact that the sandstone of Brown Edge has proved to be Redmires Flags. The Redmires Flags make up the remainder of these beds; they are medium-grained flaggy sandstones usually 20 to 35 ft thick, but absent near Moscar. I.P.S.

Fauna of the Middle Grit Group

Two sorts of Reticuloceras occur in the Reticuloceras gracile Zone: evolute forms with strong umbilical plications and involute, finely ornamented forms. Both types show similar lattice-like ornament when adult and both occur in the R. gracile Marine Band. The involute forms are R. gracile and the evolute forms are either R. gracile early form or R. gracile late form—the names not necessarily implying stratigraphical position. The R. gracile Marine Band also contains forms of Anthracoceras with strongly bilobate growth lines, Caneyella rugata (Jackson) and Dunbarella speciosa(Jackson). With the exception of Lingula at one locality no benthonic fossils are known in the R. gracile Marine Band. Some of the original type specimens of R. gracile late form came from Raddlepit Rushes within the present district (Bisat 1924, p. 117).

The three principal marine horizons of the R. bilingue Zone contain in upward succession R. bilingue early form, R. bilingue (= mut.β Bisat) and R. bilingue late form. The first two of these are evolute, and the last is relatively involute and finely ornamented. All show a greater development of the lingua than species found in the R. gracile Zone and reticulate ornament tends to be restricted to the lingua. The R. bilingue early form horizon has not been found in the eastern part of the district. Forms of Hudsonoceras ornatum occur in both the R. bilingue early form and R. bilingue late form horizons, but they have not been found in collections from the R. bilingue level. The lower marine band in Whitehall Works Borehole (see p. 228) near Chinley contains a fragment with straight crenulate transverse striae resembling Gastrioceras. The R. bilingue horizon in the same borehole contains a Reticuloceras with closely-set subcrenulate striae on the flanks, which is similar to a specimen recorded from the Macclesfield district (Evans and others 1968, table 6). The marine fauna of the zone is entirely devoid of benthonic species in this district, except for a thin 2-in band containing Lingula mytilloides within the R. bilingue Marine Band in the Whitehall Works Borehole. Records of non-marine faunas from the R. bilingue Zone are infrequent. Curvirimula ? (and plants) occurs above the R. bilingue Band in the Whitehall Works Borehole, and in the Heyden Rock on Strines Moor a thin layer with moulds of Carbonicola sp. was found, unusually in a sandstone matrix.

The typical fauna of the R. superbilingue Marine Band comprises Caneyella rugata, Dunbarella sp., Gastrioceras spp.[undescribed species with crenulate transverse striae], Homoceratoides fortelirifer Ramsbottom [type locality at Pears House Clough within the present district] (see Ramsbottom 1958, pp. 29–31) and R. superbilingue [abundant]. Donetzoceras sigma occurs rarely as does Homoceratoides aff. divaricatus (Hind). The fauna tends to be more varied in the east, where the band is thick, than in the west where it is thin. In the D. sigma Band, D. sigma is the only abundant goniatite, but R. superbilingue and Gastrioceras sp. occur rarely together with Caneyella sp. and Dunbarella sp. At one locality near Mitchell Field, an example of the gastropod Pseudozygopleura was collected. In the stream between Strines and Dale Dike reservoirs Lingula occurs some 5 to 6 ft below the D. sigma Band. W.H.C.R.

Rough Rock Group (Yeadonian, G1)

These beds comprise shales below and the Rough Rock above, overlain by a seatearth and sometimes a thin coal (see (Plate 19)). The top is defined by the base of the Gastrioceras subcrenatum Marine Band. A thin lower and a thick upper cyclothem are usually present and begin respectively with the G. cancellatum and G. cumbriense marine bands; there is some indication that the upper cyclothem splits locally.

Shales below the Rough Rock

Western area

These are in most places from 180 to 220 ft thick, though they attain 260 to 280 ft around New Mills and Fernilee. They consist for the greater part of shales, though some thin sandstones and siltstones are present in the upper part; locally thin sandstones at the top join the Rough Rock. The most important stratigraphical features are the presence of the Gastrioceras cancellatum and G. cumbriense marine bands respectively at and near the base of the shales.

The G. cancellatum Marine Band consists of dark calcareous shales, usually from 1.5 to 3 ft thick. In most places some 20 to 26 ft of shale separate the G. cancellatum and G. cumbriense bands. Around the Goyt Trough these shales frequently contain a thick contorted band overlying the G. cancellatum horizon and a thinner contorted band a few feet below the G. cumbriense Band. To the north-west, around Rowarth, the shales expand to about 80 ft. In the Fernilee No. 1 Borehole, Planolites sp., Cochlichnus kochi and fish debris occur between the G. cancellatum and G. cumbriense marine bands.

The G. cumbriense Marine Band (see also pp. 239–42) usually consists of 5 to 14 in of dark calcareous shale, though the Fernilee No. 1 Borehole showed the unusual thickness of 2 ft 11 in A thin Lingula band has been observed close to the base of the band near Errwood.

The shales overlying the G. cumbriense Band are usually poorly exposed. What must be nearly the full thickness, 220 ft, was proved in Fernilee No. 2 Borehole. This showed shales with a few thin siltstones and flaggy sandstones in the upper part. The top 90 ft yielded Naiadites sp. [juv.] at three levels. The uppermost of these, about 28 ft below the Rough Rock, recalls the occurrence of non-marine bivalves (Carbonicola) in a similar position beneath the Rough Rock at Langsett (Bromehead and others 1933, p. 163). The uppermost beds show a gradual passage upwards where the Rough Rock Flags (see below) occur and a more abrupt change where the Rough Rock only is present.

Eastern area

Here only 100 to 130 ft of shales occur between the G. cancellatum Band and the Rough Rock. However, the interval between the G. cancellatum and G. cumbriense bands is greater than in the west, being about 70 ft. The general features of the marine bands are as described for the western outcrops, the only additional feature of note being the local development of a band 2 ft thick with sporadic Lingula beneath the G. cumbriense Band at Holes Clough, Bradfield. This is in the position of the Lingula band noted above near Errwood.

Rough Rock

The Rough Rock consists usually of a single massive coarse sandstone, often current-bedded and in places with small pebbles. Finer-grained, flaggy beds are frequently developed at the base and the most distinctive of these, though of local development only, have been separately shown on the Six-inch maps (though not on the One-inch) as 'Rough Rock Flags'.

The thickness of the Rough Rock is somewhat variable (see (Plate 19)). In the north-western outcrops it is 50 to 60 ft between Glossop and Chinley, but this increases westwards to 85 ft at Broadbottom, where it is well exposed in the deep gorge of the River Etherow, and 163 ft in a borehole at Mellor. In the southern part of the Goyt Trough a lower leaf of up to 40 ft of flaggy sandstones develops in places and this is separated from the coarse upper leaf, about 100 to 110 ft thick, by a few feet of shale. Near Kettleshulme the Rough Rock thins, appears to split, and is only some 20 to 30 ft in thickness.

On Mellor Moor the Rough Rock is split into two equal leaves and there is some indication from a borehole at Capstone (see p. 244) that the base of this parting may represent the horizon of the Sand Rock Mine of Lancashire. The horizon is known from the Romiley Dyeworks Borehole (Taylor and others 1963, p. 152) where it is separated from the Six-Inch Mine by only 11 ft of measures, including the seatearth of the latter.

The main bed of the Rough Rock is underlain in places by up to 30 ft of Rough Rock Flags. These beds are best developed on Chinley Churn where they are regularly bedded fine-grained micaceous flaggy sandstones. At this locality they were formerly quarried and even mined as roofing flags. Less distinctive flaggy beds are also present near the base of the Rough Rock and as thin leaves which split off it, for example, at Rowarth.

On the eastern side of the district outcrops of Rough Rock are restricted. The main characters are as already described and the thickness is 50 to 60 ft. The only noteworthy feature is the splitting into an upper coarse-grained leaf and a lower fine-grained leaf in the vicinity of Brown Edge and Stanage.

A regional study of the Rough Rock by Shackleton (1962), which includes the present district, described its petrography and sedimentary structures. The rock is an arkose, containing about 20 per cent feldspar (mainly microclineperthite with a little oligoclase-andesine) with small quantities of muscovite, biotite, clay minerals and rarely calcite. Heavy minerals include tourmaline, rutile, zircon, garnet and apatite.

Beds above Rough Rock

The Rough Rock is overlain in western outcrops by a seatearth some 2.5 ft thick which locally bears a thin coal, the Six-Inch Mine. To the west of Mellor the coal occurs as a single thin seam of about 6 in; to the east, however, a split seam (for example, coal 5 in, dirt 3 in, coal 5 in) is present. The Shaw Farm

Borehole, near Brook Bottom, proved the thickest section of the coal in the district: coal 11.5 in, dirt 7 in, coal 5.5 in. To the south of Brook Bottom the Six-Inch Mine has not been found.

To the south of Whaley Bridge about 2 ft of seatearth rest on the Rough Rock. At Fernilee 2.5 ft of unexposed measures, probably shale, lie between the seatearth and the G. subcrenatum Marine Band, but in the Fernilee No. 2 Borehole the marine band rests directly on the seatearth.

On the eastern side of the district, around Ughill, the seatearth is well developed as the Pot Clay of the Sheffield area (Eden and others 1957, pp. 36–7These authors included the Pot Clay in the Coal Measures for descriptive purposes.). It is about 3.5 to 6 ft thick and is overlain by the Pot Clay Coal up to 2 in thick. A small thickness of shale separates the coal and marine band. Workings for the Pot Clay at Sugworth show 10 in of shale with a thin Carbonicola band towards the base; this was first noted by Eagar (1953, p. 174). I.P.S.

Fauna of the Rough Rock Group

Faunally the G. cancellatum Marine Band is composite and contains three faunas characterized by, in ascending order: G. branneroides Bisat; G. cancellatum Bisat and R. superbilingue; Agastrioceras carinatum (Frech) and G. crencellatum Bisat. The lowest of these has not been recognized in collections made in the district. Anthracoceras sp., Caneyella multirugata (Jackson) and Dunbarella elegans (Jackson) are the other fossils typically found in this marine band; Homoceratoides occurs rarely.

In the G. cumbriense Marine Band, G. cumbriense Bisat and G. crenulatum Bisat are the typical goniatites, but Homoceratoides aff. divaricatus is commonly found. Aviculopecten aff. losseni (von Koenen) is characteristic of this level, but is not always found. Other fossils include Caneyella multirugata, Dunbarella sp. and Anthracoceras. A thin band with Lingula occurs about 7 in below the G. cumbriense Band near Errwood. W.H.C.R.

In the Fernilee No. 2 Borehole the shales below the Rough Rock contained sporadic, small Naiadites sp. cf. productus (Brown) and Cochlichnus spp.at several horizons. The widespread musselband occurring immediately below the G. subcrenatum Marine Band in the adjacent parts of the Lancashire and Yorkshire coalfield (Eagar 1953) has been found at Bradfield Moors; the fauna included 'Anthraconaia' lenisulcata (Trueman) and Geisina arcuata (Bean). MonograptusA.C.

Details

Kinderscout Grit Group and underlying beds

Edale Shales

Edale valley (see (Figure 16))
Cravenoceras leion Zone (E1a)

Beds of the Cravenoceras leion Zone (E1a) do not crop out at Edale and they are known only from the Edale Borehole [SK 1078 8493], 665 yd E. 11°S. of Highfield. The lowest beds, lying between 305 and 325 ft, are described by Hudson and Cotton (1945, pp. 4, 12) as shales with pebbles of limestone and "limy shale" between 309 and 315 ft. The pebbles are evidence of the strong erosion of the

Carboniferous Limestone of the upturned edge of the block south of Mam Tor (see p. 113). The fauna, with names amended where necessary, consisted of Caneyella membranacea, Posidoniella sp., Eumorphoceras sp. and Orthoceras sp. between 315 and 325 ft, and C. membranacea, cf. C. semisulcata, Cravenoceras leion, Eumorphoceras tornquisti, E. cf. E. tornquisti between 305 and 315 ft. From 252 to 305 ft the borehole proved "smooth grey shales" with occasional marine fossils and abundant fish and plant debris. The following were identified: "rare posidoniellids" from 265 to 305 ft, Pseudamussium sp. and Sanguinolites cf. angustatus (Phillips) from 286 to 291 ft, and Orthoceras sp. from 296 to 302 ft. The higher part of the zone, from 77 to 252 ft, consisted of "grey silty mudstones, fine micaceous shales, or fine siliceous siltstones". Plant debris occurred between 152 and 252 ft.

Eumorphoceras pseudobilingue Zone (E1b)

The Eumorphoceras pseudobilingue Zone (E1b) is represented at surface by the lowest exposed beds in the core of the Edale Anticline (see (Plate 16A)) and in the Edale Borehole by the beds from 40 to 77 ft. In the River Noe beds of E1b age occur between about 110 yd and 420 yd upstream from the railway-bridge. The lowest strata (Edale 79)Numbers preceded by the word 'Edale' indicate locality numbers of Hudson and Cotton (1945). , some 4 ft in thickness, are exposed [SK 1063 8495] 700 yd N. 38°W. of Manor HouseUpstream limit of Edale 79: [SK 1058 8497]., where they yielded Posidonia cf. corrugata, Posidoniella cf. laevis (Brown), Anthracoceras sp., Eumorphoceras pseudobilingue [old-age form] and fish debris. The overlying beds, thin-bedded argillaceous limestones with shale partings, about 20 ft in thickness, yielded P. cf. corrugata and Dimorphoceras sp. at a locality (Edale 80) [SK 1073 8491] 620 yd N. 33°W. of Manor House and fish debris in a nearby exposure (Edale 83) [SK 1083 8483]Hudson and Cotton (ibid., p. 4) state that the lowest 30 ft of beds at the surface are the same as the uppermost 30 ft of the borehole. The latter figure is approximately correct if taken from the point (37 ft) at which coring commenced.. The uppermost beds of the zone are dark shales with some thin ironstones, about 23 ft in thickness.

The beds of this zone in the Edale Borehole consisted of "shales, silty shales and occasional siliceous siltstones from 40 to 77 ft" yielding Posidonia cf. corrugata [small form] P. cf. membranacea, P. cf. radiata (Hind), Posidoniella cf. laevis and Posidoniella variabilis. I.P.S.

Cravenoceras malhamense Zone (E1c)

The Cravenoceras malhamense Zone (E1c) is exposed on the northern flank of the Edale Anticline along the banks of the Noe east of Highfield, where it is nearly 50 ft thick. The lowest 15 to 20 ft consist mainly of shales and mudstones with thin dolomitic siltstones and limestones, and contain fairly abundant fossils, as noted from outcrops in the southern flank of the anticline by Hudson and Cotton (ibid., p. 11). An outcrop of these beds in the north bank of the Noe [SK 1047 8506] showed over 15 ft of thin-bedded shale with thin hard dolomitic silty limestones and dolomitic limestones, the latter containing minute fragments of shells, foraminifera, bryozoa and ?ostracods. These beds yielded Caneyella membranacea, Posidonia corrugata, Cravenoceras malhamense, and in carbonate bullions near the base, Dimorphoceras sp. They are overlain by a sequence of alternating shales and hard dolomitic siltstones with thin dolomitic limestones, approximately 20 ft thick, in which fossils are sparse and poorly preserved. The uppermost part of the zone is made up of largely unfossiliferous shales and mudstones up to 10 ft thick, poorly exposed in both banks of the Noe at a point [SK 1042 8510] 85 yd below the road-bridge to Upper Booth, and for 40 yd downstream. G.D.G. The zone is represented on the south-east side of the Edale Anticline by shale outcrops in the Noe between a point [SK 1092 8479] 110 yd upstream from the railway-bridge and 210 yd downstream from the bridge:

feet

Shale, dark, partly calcareous with thin dolomitic shaly siltstones in lower part; Caneyella membranacea, C. aff. membranacea [elongate form], Posidonia aff. corrugata, Posidoniella aff. vetusta, Cravenoceras malhamense, C. sp. at 5 to 10 ft from base

about 35

Shale, dark with thin silty bands; C. membranacea, Myalina aff. compressa Hind, Monograptus sp., Posidonia aff. corrugata, P. aff. vetusta, Pseudamussium sp.

4

Shale, hard calcareous, with thin calcareous siltstone bands up to 4 in and carbonate bullions up to 9 in thick at base; C. membranacea, C. membranacea [elongate form], Posidonia aff. corrugata, Hyolithes sp., Cravenoceras malhamense, C. sp. [smooth form], Dimorphoceras sp., Kazakhoceras sp.

6

All the fossil records are from Hudson and Cotton (ibid., p. 11).

Excavations for the sump for the Edale Borehole in shale and siltstone yielded Posidonia membranacea, Posidoniella cf. laevis and P. variabilis from this zone. From Hudson and Cotton's description of Fib (ibid., p. 10) it is clear that these authors refer all the beds in the borehole down to 40 ft to En, although only the lowest 3 ft of these was cored.

Eumorphoceras bisulcatum Zone (E2a)

The Eumorphoceras bisulcatum Zone (E2a) is represented by some 80 ft of shale with carbonate bullion and thin dolomitic siltstone bands cropping out in the banks of the Noe over a distance of a mile between the most easterly exposures of the C. malhamense Zone near Barber Booth and the most westerly exposure with Cravenoceratoides edalensis [SK 1285 8512], (see p. 190). These beds yielded fish debris only, at a point 215 yd downstream from the railway-bridge. The upper part of the zone is exposed in the river farther downstream. At a point [SK 1140 8475] about 0.25 mile N.E. of Manor House, the following section was measured:

feet

inches

Shale, grey 'sulphurous', platy in lower part: 3-in ironstone at 3 ft from base: rare goniatites

10

0

Shale, platy decalcified

3

Shale, pale grey 'sulphurous'

1

4

Ironstone

4 in to 5

Shale, soft grey 'sulphurous'

9

Shale, grey

3

6

Shale, soft ferruginous

2

Ironstone

0 in to 6

Shale, pale grey

3

0

Shale, decalcified ferruginous

3

Ironstone

2

Shale, grey

10

The fossils recorded by Hudson and Cotton (ibid., p. 10) from this section (Edale 111) are: Posidonia sp., Pseudamussium jacksoni Demanet, P. sp., Cravenoceras cowlingense group, C. sp. [smooth form], Dimorphoceras sp., Kazakhoceras cf. scaliger, Orthoceras sp., crinoid columnals, and (specified as occurring in the lower part of the section)Posidonia cf. corrugata and Eumorphoceras bisulcatum. A similar fauna including E. bisulcatum was also recorded from the confluence of the Noe with a small stream (Edale 112) [SK 1163 8478], nearly 0.5 mile E.N.E. of Manor House. I.P.S.

The total thickness of the zone exposed in the River Noe near Upper Booth is not much more than 80 ft, but a few feet at the top may be faulted out, as suggested by Hudson and Cotton (ibid., p. 10). Outcrops occur in the Noe from 40 yd below the confluence with Crowden Brook [SK 1020 8522] to 20 yd downstream (Edale 74) [SK 1037 8512] from the road-bridge to Upper Booth, where Hudson and Cotton (ibid., p. 11) record C. cowlingense in the basal beds of the zone. At the road-bridge [SK 1035 8513] to Upper Booth thin bands of cross-bedded fine sandstone, partly decalcified, partly dolomitic, and up to 1 in thick, are present in interbedded shales and dolomitic siltstones in the northern bank. An exposure on the south bank of the Noe [SK 1024 8520] consists of 18 ft of shale with ironstone bands and containing Anthracoceras or Dimorphoceras sp., overlying 6.5 ft of hard shaly mudstone with P. corrugata elongata Yates, Eumorphoceras bisulcatum and Kazakhoceras scaliger. The lowest occurrence of E. bisulcatum is estimated to be 40 to 45 ft above the base of the zone at this locality. Farther east, Hudson and Cotton (ibid., pp. 10–11) record a fauna from shale with thin ironstone bands on the north bank of the Noe (Edale 124) [SK 1237 8519] 200 yd S. 30° E. of Edale station and a similar outcrop (Edale 123a) on the south bank by the footbridge 60 yd upstream, which they refer to as "E1d" recent collecting has shown the fossils to be mainly fragments of old-age Eumorphoceras. Though determination of horizon is not possible, it seems probable that these outcrops are of E2a age as defined on p. 167.

Cravenoceratoides nitidus Zone (E2b)

The Cravenoceratoides nitidus Zone (E2b) has a total thickness of about 60 ft, but it is difficult to make a reliable estimate due to faulting and poor exposure. It consists of shales and mudstones with subsidiary ferruginous siltstones, thin ironstone bands, carbonate bullion horizons and a distinctive bed of dolomitic siltstone and dolomite containing a brachiopod-trilobite fauna in the upper part of the zone. Most of the zone, including the lowest beds with the Cravenoceratoides edalensis fauna are probably cut out by faulting in the vicinity of Upper Booth. The following section of the upper part of the zone and the basal part of the Nuculoceras nuculum Zone occurs on the east bank of Crowden Brook [SK 1022 8526],

feet

inches

Mudstone

5

6

Siltstone, ferruginous, passing locally into ironstone

3 in to 5

Mudstone, with thin ferruginous silty bands

9

0

Siltstone; Posidoniella aff. vetusta, Nuculoceras stellarum

9

Not exposed

about 2

0

Mudstone

5

0

Mudstone, black

1

6

Mudstone, hard black silty

1

0

Dolomite, pale grey fine-grained hard splintery and partly laminated, with ferruginous silty partings and fragmented shell debris

4

Mudstone, hard black silty, with thin lenticular dolomite partings; P. aff. vetusta, nautiloid cf. Tylonautilus, Cravenoceras?, Eumorphoceras cf. rostratum and Weberides sp. mainly concentrated in a band 14 in above the base

2

6

Productus hibernicus, Rugosochonetes sp. and E. rostratum have been identified in Hudson and Cotton's collections from this exposure (Edale 45), which confirms the position of the brachiopod-trilobite-Ct. nititoides fauna as being 12 ft below the base of the succeeding zone, as represented by N. stellarum.

Beds of E2b age crop out extensively in the vicinity of Grindsbrook Booth. The lowest horizon identified is on the east bank of Grinds Brook [SK 1237 8589], just north-northeast of Edale church, where 3 ft of shale contains poorly preserved Cravenoceratoides sp., possibly Ct. edalensis or Ct. bisati. Exposures on both banks 20 yd farther upstream have yielded Posidonia corrugata, Anthracoceras or Dimorphoceras sp., Cravenoceratoides sp. and fish fragments. The dolomite horizon has not been identified, but the following section occurs on the east bank of Grinds Brook by the bridge [SK 1233 8604]:

feet

Shale, soft

3

Shale, hard flaggy rather silty, with large calcareous bullions at the base; athyroids indet., Orbiculoidea nitida, Productus hibernicus, Rugosochonetes sp., Posidonia aff. vetusta, Eumorphoceras sp., Kazakhoceras sp., and crinoid columnals

2

Shale, with soft black bands, thin hard ferruginous siltstone bands and small carbonate bullions

11

The abundance of P. aff.vetusta indicates proximity to the N. stellarum band at the base of the overlying N. nuculum Zone.

The E2b Zone strata crop out sporadically in the banks of the Noe between its confluence with Grinds Brook and the small reservoir south-east of Nether Booth. Black iron-stained shale with Ct. edalensis crops out in the south bank [SK 1285 8512]. This outcrop is either the type locality, or is very near to the type locality for Ct. edalensis. To the east, the upper part of the zone and the basal part of the succeeding E2c Zone are present in exposures along the river near Skinner's Hall, between the footbridge [SK 1295 8516] leading from Edale to Hollins Cross and the junction with Oller Brook [SK 1326 8535], a composite section being:

Still farther east, shale with Ct. edalensis is again exposed in both banks of a bend in the Noe [SK 1332 8531] 1130 yd E.2°S. of Edale station, and outcrops, probably of upper E2b and lower E2c strata, occur for another 300 yd downstream to the north-east.

feet

Shale, ferruginous; P. corrugata, P. aff. vetusta and N. stellarum in upper 1 ft

10

Shale, flaggy, with 2-in band of hard dolomitic siltstone at base containing Lingula mytilloides, Productus hibernicus, Rugosochonetes sp., Euchondria aff. levicula Newell, Epistroboceras?, Cravenoceratoides nititoides, Dimorphoceras sp., Eumorphoceras cf. rostratum, Weberides sp. and crinoid debris

2

Shale, soft, with sporadic carbonate bullions containing Posidonia corrugata and Cravenoceras sp.

8

Shale, hard thin-bedded, with P. corrugata, Posidoniella variabilis, Cravenoceras cf. holmesi and ortho cone indet.

5

Beds of this zone have been proved in the river banks south-east of Nether Booth and over 30 ft of strata, including the brachiopod-trilobite horizon, are exposed in the south bank of the small reservoir [SK 1457 8580] some 500 yd S.E. of Nether Booth, as indicated by Hudson and Cotton (ibid., pp. 9–10). This outcrop (Edale 181) was inaccessible during the present survey. G.D.G.

The E2b Zone, although probably present in Whitemoor Sitch, is poorly exposed; it is represented, and this somewhat doubtfully, by an outcrop [SK 1075 8455], where Posidonia corrugata was collected. I.P.S.

Nuculoceras nuculum Zone (E2c)

The Nuculoceras nuculum Zone (E2c) is about 60 ft thick near Upper Booth, but possibly less than 50 ft in Grinds Brook, and it may be even thinner farther east. It consists of a fairly uniform sequence of shale and mudstone with a few thin, in places slightly dolomitic, siltstone beds and rare carbonate bullion horizons. The exposure near the confluence of Crowden Brook with the River Noe, containing the basal N. stellarum band in the uppermost 1 ft, has already been noted on pp. 189–90. This fossil has also been recorded from a number of localities nearby (Edale 42, 43, 46) (Hudson and Cotton ibid, pp. 8–9). The occurrence of this band in the Skinner's Hall section has also been mentioned.

N. nuculum, which is characteristic of the middle and upper parts of the zone, is present in a number of localities near Upper Booth. It has been identified in collections made by Hudson and Cotton from a locality in Crowden Brook (Edale 49) [SK 1025 8540] and is recorded by them together with Cravenoceratoides fragilis, from an outcrop a little higher upstream (Edale 51) [SK 1025 8548] where the following succession, typical of the lithology of the zone, is exposed:

feet

Shale, with carbonate bullions 3 ft from top

9

Mudstone, black

1.5 ft to 2

Limestone, dolomitic

0.5 ft to 2.5

Shale, black

2

G.D.G.

N. nuculum has also been found during the re-examination of collections made by Hudson and Cotton from the north bank of the Noe (Edale 32) [SK 1007 8535]. Together with Ct. fragilis, it had been recorded by these authors from a shale outcrop in a small stream a short distance to the south-west (Edale 39) [SK 0996 8519]. G.D.G., I.P.S.

Farther east, Hudson and Cotton record cf. N. nuculum from the base and Homoceras subglobosum from the upper part of a section (Edale 148) in Grinds Brook [SK 1221 8616], 0.25 mile N.15°W. of Edale church, where rather fissile shale, 15 ft thick, is exposed in the east bank.

In the south bank of the Noe [SK 1365 8542], 1010 yd E.32°S. of Ollerbrook Booth, the following section is present, partially repeated by faulting:

feet

inches

Shale

9

0

Shale, silty with dolomitic siltstone lenses

0 to 5

Siltstone, dolomitic; Glabrocingulum sp., Actinopteria persulcata (McCoy)

4 in. to 5

Mudstone

5

6

Shale, silty ferruginous

2

9

A short distance to the east [SK 1370 8545], an exposure, complicated by faulting and slipping, is probably in the same strata; it has yielded A. persulcata, Leiopteria longirostris Hind, P. corrugata and Posidoniella sp. Hudson and Cotton (ibid., pp. 8, 9) record N. nuculum from the base and H. subglobosum s.l. from the top of this exposure (Edale 176).

Homoceras subglobosum (H2a)

The Homoceras subglobosum (H2a) and Homoceras beyrichianum (H2b) zones consist of mudstones, partly shaly, over 70 ft thick, with sporadic carbonate bullion horizons and with fossils mainly in the H. subglobosum Zone. The basal strata are exposed in the east bank of Crowden Brook [SK 1027 8552] at Upper Booth:

feet

Shale, with black bands; a line of carbonate bullions at the base containing H. subglobosum

17

Mudstone, black, with thin shaly bands

9

As previously stated, Hudson and Cotton recorded H. subglobosum from a locality (Edale 148) in the east bank of Grinds Brook [SK 12218616] at Grindsbrook Booth. Posidoniella cf. variabilis was found 3 ft above the base of this outcrop during the present survey. Hudson and Cotton also record H. subglobosum s.l. from the top of an outcrop (Edale 176) on the south bank of the Noe [SK 1370 8545] (see p. 191). The following section of beds of H1a age is present in the River Noe [SK 1475 8597], 710 yd S.15°E. of Cough Farm and for a further 110 yd downstream:

feet

Shale, with thin ironstone nodules

4

Mudstone, black, with ferruginous shale bands

2

Not exposed

about 2

Shale.

2

Not exposed

about 2

Shale with large carbonate bullions; Aviculopecten sp., cf. H. subglobosum

2

Shale

2

Not exposed

2

Shale, with black mudstone bands and large carbonate bullions at base

2

Shale

5

Shale, ferruginous, with large carbonate bullions

0.75

Mudstone, soft

1

Shale

2.5

Mudstone, with soft black bands

1

Shale, ferruginous, with thin nodular ironstone bands and large carbonate bullions containing H. subglobosum

0.75

Shale

6

Not exposed

about 4

Shale, black

2

Shale, silty ferruginous, with ironstone lenses and carbonate bullions containing H. subglobosum

0.25

Shale

2

About 70 yd downstream [SK 1477 8611] the following section is exposed in the north bank:

feet

Shale, black in lower part, with 2-in silty ironstone at base

3.25

Shale, black towards base, with rare disseminated plant debris and very thin lenticular coal partings near top; H. subglobosum and Homoceras sp. about 2.5 ft above base

6

Shale, black, with interbedded ferruginous silty shale and thin nodular ironstone bands

2.25

Some of the Homoceras sp. recorded in this section resemble the Homoceras sp. nov. figured by Ramsbottom, Rhys and Smith (1962, pl. 6, fig. 11) from between the H. beyrichianum and H. subglobosum faunas.

No outcrops containing H. beyrichianum were proved in the Edale valley during the present work.

Hudsonoceras proteus (H2a), Homoceras undulatum (H2b) and Homoceratoides prereticulatus (H2c)

The Hudsonoceras proteus (H2a), Homoceras undulatum (H2b) and Homoceratoides prereticulatus (H2c) zones are represented by over 30 ft of shale and mudstone, with sporadic bullion horizons. A good section can be seen in a series of outcrops in Crowden Brook for a distance of over 50 yd downstream from a point [SK 1025 8563], 640 yd N. 3°E. of Highfield. Hudson and Cotton record Homoceras smithii and Hudsonoceras proteus from this section (Edale 57). The higher beds containing the Homoceras undulatum and Homoceratoides prereticulatus horizons are apparently not exposed in Crowden Brook.

The lowest fauna is present in Grinds Brook [SK 1222 8626] near Grindsbrook Booth, in the following section:

feet

Shale, black

3

Carbonate bunions with Hd. proteus

Shale

3

Carbonate bullions with H. smithii

Shale, with rare thin bands of sandy clay; Caneyella semisulcata near base

10

The bullion band with Hd. proteus was also proved about 80 yd upstream (Edale 152) by Hudson and Cotton (ibid., pp. 6–7). The higher 112 faunas have not been proved in Grinds Brook and the whole zone is virtually unexposed in the banks of the Noe south-east of Nether Booth. G.D.G.

An important section in H2 is that [SK 0957 8554] on the left bank of the Noe at the junction with Grain Clough:

feet

Shale, pale grey 'sulphurous' with ferruginous bands at 7 ft above base

17.5

Shale, soft black, with bullion at base; Anthracoceras or Dimorphoceras sp., Homoceras undulatum

2

Shale, grey 'sulphurous'

2.5

Shale, soft black; Caneyella semisulcata, Anthracoceras or Dimorphoceras sp., Homoceras cf. smithii

1.5

Shale, grey 'sulphurous'

7

Shale, soft black; C. semisulcata, H. smithii, Hudsonoceras proteus

1.5

Beds a few feet higher in the succession are exposed in a meander [SK 0953 8551] about 50 yd upstream from the last section. Here (Edale 14) Hudson and Cotton (ibid., pp. 6–7) record Homoceratoides cf. prereticulatus.

In Whitemoor Sitch a H2c fauna was obtained by Hudson and Cotton (ibid., pp. 6–7) from the right bank of the stream (Edale 100) [SK 1045 8428]: Dunbarella cf. mosensis (de Koninck), Homoceras sp. cf. H. diadema (Beyrich) group, Homoceratoides prereticulatus. H2 faunas are also present in two places in Harden Clough. The lower of these [SK 1244 8446] occurred in a 6-in band of dark, partly decalcified shale, which yielded Homoceras smithii and Hudsonoceras proteus. Some 30 ft higher in the succession and 60 yd farther upstream [SK 1246 8440] the top of the Homoceras stage is marked by a band yielding Posidonia sp., Anthracoceras or Dimorphoceras sp., Homoceras sp., Homoceratoides aff. prereticulatus. I.P.S.

Reticuloceras circumplicatile Zone (R1a)

The Reticuloceras circumplicatile Zone (R1a) consists mainly of shale with sporadic thin ferruginous siltstone and ironstone bands, about 80 ft thick. Homoceras magistrorum has not been proved in the Edale valley. In Crowden Brook the lowest exposure of the zone [SK 1025 8566] above Upper Booth consists of shale, 17 ft thick, with carbonate bullions near the base, containing Caneyella sp., Dunbarella sp. nov., Anthracoceras or Dimorphoceras sp., Homoceras sp., Reticuloceras sp. of R. circumplicatile group and R. aff. todmordenense. In the west bank, about 50 yd upstream, but apparently little higher in the succession, 6 ft of shale with a 4-in ironstone band near the top contain Caneyella sp., Dunbarella sp., Posidonia sp., an orthocone nautiloid, Homoceras cf. henkei, Reticuloceras cf. pulchellum and Reticuloceras sp. Higher beds are seen in the east bank a few yards farther north [SK 1022 8572] and consist of 12 ft of shale with silty ironstone bands containing an orthocone nautiloid, Homoceras sp. of H. eostriolatum group and Reticuloceras sp.

A good section of lower R1a strata is present in the east bank of Grinds Brook [SK 1214 8635] 25 yd E. of Grindslow House:

feet

Shale, soft

5

Shale, hard splintery fissile

4

Shale, soft black fissile

7

Shale, with thin ironstone bands and very thin pale brown clay bands; Dunbarella sp., Posidoniella sp., Homoceras sp. and Reticuloceras sp. of R. ? todmordenense group in a band 4 ft above base

6

Siltstone, ferruginous, with ironstone nodules; Posidoniella sp., Reticuloceras sp.

0.25

Shale, with thin ferruginous siltstone bands; Dunbarella sp., Anthracoceras or Dimorphoceras sp., Homoceratoides sp., R. cf. pulchellum, R. cf. subreticulatum and Cypridina sp. in a band 3 ft above base

6

Shale, soft black at base, becoming hard with thin ferruginous siltstone bands towards the top

15

Upper R1a and possible lower R1b beds are almost continuously exposed for 50 yd upstream from a point [SK 1215 8639] 60 yd N.W. of Grindslow House; they consist of over 30 ft of soft shale containing rare Dunbarella sp. and with sporadic ferruginous siltstone nodules and ironstone bands up to 3 in thick yielding Dunbarella cf. speciosa, Posidonia?, Promytilus? and Reticuloceras sp.

Three outcrops of R1a age have been proved in Ollerbrook. In the west bank [SK 1285 8611] just north of Ollerbrook Booth 9 ft of shale contain Dunbarella sp. and Reticuloceras sp. of R. ? todmordenense group in a band 2 ft above the base. Some 30 yd upstream [SK 1285 8614], 4 ft of shale yield Dunbarella sp., R. cf. todmordenense and R. cf. circumplicatile from a band 1 ft above the base, and an exposure a farther 15 yd upstream on the east bank [SK 1285 8615] shows 4 ft of shale with Dunbarella sp. and Reticuloceras cf. paucicrenulatum.

No fauna of R1 age has been proved from the River Noe south-east of Nether Booth, where the banks are largely obscured by head and landslip. The only fossiliferous beds exposed are on the south bank [SK 1487 8612], where indeterminate goniatites occur in shale with carbonate bullions. G.D.G.

In the upper reaches of the River Noe, R1a faunas are present at several places, the zone being here about 75 ft in thickness. The lowest exposure (Edale 9) [SK 0939 8566], above Lee House, yielded Dunbarella cf. rhythmica (Jackson), Anthracoceras or Dimorphoceras sp., Homoceras sp. and Reticuloceras aff. subreticulatum [crenulate flanks]. Some 40 yd farther upstream (Edale 8) Hudson and Cotton (ibid., p. 5) record Dunbarella cf. carbonaria (Hind), D. rhythmica, D. sp., Posidoniella minor (Brown), P. minor Hind non Brown, Dimorphoceras sp., Homoceras henkei group, H. sp. cf. H. striolatum group.

Faunas here referred to the R1a. Zone were found by Hudson and Cotton (ibid., p. 5) in Whitemoor Sitch, in shales with large bullion, about 70 ft thick: (a) (Edale 100a) [SK 1039 8424], nearly due south of the mouth of Cowburn Tunnel; Dunbarella sp., Dimorphoceras splendidum ? (Brown), Homoceras sp., Reticuloceras inconstans (Phillips) group, R. cf. pulchellum: (b)(Edale 100b) 40 yd upstream from the last locality: Homoceras sp., Reticuloceras adpressum, R. paucicrenulatum. I.P.S.

Reticuloceras nodosum (R1b) Zone

The Reticuloceras nodosum (R1b) Zone, about 40 ft in thickness, consists of shale and mudstone, with distinct thin siltstone beds and with locally abundant groups of thin ironstones. An outcrop in the west bank of Crowden Brook [SK 1021 8575], above Upper Booth, contains a low R1b or possibly high R1a fauna:

feet

inches

Shale, soft black

2

0

Siltstone, sandy, hard blocky ferruginous

4 in to 8

Shale with soft black bands and ironstone bands 0.5 in to 2 in thick

6

0

Shale, black in lower part

7

6

Clay, pale brown sandy

0.5

Shale, black, with ferruginous nodules; Homoceratoides divaricatus and Reticuloceras spp.(?nodosum and todmordenense groups)

1

0

Shale with rare disseminated plant debris near base

5

6

Shale with abundant ferruginous siltstone bands 0.25 to 0.75 in thick

3

0

In Grinds Brook [SK 1212 8647], near Grindslow House, R. nodosum has been found in ironstone nodules contained in 8 ft of shale with abundant very thin ironstone bands, probably from near the top of the zone.

The widest range of R1b faunas has been proved in Oiler Brook. In the east bank [SK 1281 8626], 760 yd N.E. of Edale church, 8 ft of mudstone with shaly bands contain Dunbarella speciosaand Reticuloceras sp. (? dubium group) in the lowest 2 ft, probably the basal horizon of the zone. In the east bank 30 yd upstream [SK 1281 8629], 8 ft of shale, hard and platy near top, contain Caneyella squamula (Brown), D. speciosa, Anthracoceras or Dimorphoceras sp., Homoceras? and Reticuloceras sp. in the lower 4 ft. About 15 yd farther upstream on the same side [SK 1281 8630], the following section is exposed:

feet

Shale with a thin ferruginous siltstone band in the lower part

4

Shale

1.5

Mudstone, soft black; Posidoniella sp., Anthracoceras or Dimorphoceras sp., Ht. divaricatus and Reticuloceras sp. (nodosum group)

1

Mudstone, black, alternating with thin bands of hard ferruginous shale

1.5

Shale

2

In the upper reaches of the Noe, an R1b fauna was obtained by Hudson and Cotton (ibid., p. 5) from a point (Edale 6) [SK 0932 8572], 0.25 mile W.N.W. of Lee House: Coelonautilus sp. and Reticuloceras inconstans group. The zone is about 65 ft thick in this vicinity.

The following section was measured on the hillside [SK 1000 8470] near The Orchard:

feet

Base of Mam Tor Beds

Shale, with thin sandstone bands in top 6 ft

18

Shale, soft ferruginous and decalcified

0.75

Mudstone, grey

13

Shale, dark; Caneyella cf. rugata, Dunbarella rhythmica, orthocone nautiloids, Dimorphoceras sp., Homoceras cf. striolatum, Hudsonoceras ornatum, Reticuloceras cf. moorei Bisat and Hudson, R. cf. nodosum and mollusc spat; a 15-in band of grey 'sulphurous' mudstone with Dunbarella sp. at 6 in from base

3

Mudstone, grey; Dunbarella sp. at 3 in from top

6

Not exposed

5

Mudstone, grey

10

G.D.G.

The fauna is indicative of the R1b Zone though there is room for some beds of R1c age at the top of the section.

In Whitemoor Sitch the R1b Zone consists of some 70 ft of shales with some bands of bullions. A fauna indicative of the zone was collected [SK 1029 8412] 400 yd S.S.W. of the Cowburn Tunnel entrance: Caneyella cf. squamula, Dunbarella rhythmica, Posidonia sp. nov., Promytilus foynesianus (Baily), Homoceras sp., Reticuloceras cf. moorei, R. cf. nodosum, mollusc spat. Another locality nearby, 25 yd downstream, yielded Homoceras sp. and R. nodosum group. I.P.S.

Reticuloceras reticulatum (R1c)

Beds of the Reticuloceras reticulatum (R1c) Zone within the Edale Shales appear to be less than 30 ft thick on the northern side of the Edale valley, and consist of shales and mudstones becoming increasingly silty towards the top, and with fairly abundant thin ironstone and ferruginous siltstone bands. A composite section from Crowden Brook [SK 1021 8578] some mile N. of Upper Booth and for a further few yards upstream is:

feet

inches

Base of Mam Tor Beds

Siltstone, flaggy

1

0

Shale, silty, with micaceous laminae and rare thin silty ironstone bands

9

6

Ironstone

1

Shale, hard slightly silty, with ironstone nodules near base

1

0

Ironstone

1.5

Shale, hard slightly silty, with sporadic thin ironstone bands

4

6

Siltstone, sandy ferruginous

8

Similar sections can be seen in Grinds Brook [SK 1208 8649], in Oiler Brook [SK 1281 8634] and in Lady Booth Brook [SK 1415 8622] immediately south of the small dam. The following section in a landslip-scar on the south side of the Noe [SK 1500 8604], 750 yd S.E. of Gough Farm is in the highest beds of the Edale Shales:

feet

inches

Base of Mam Tor Beds

Shale, silty, with thin ironstone bands in upper part

4

0

Carbonate bullions with indeterminate goniatites

Shale, silty

1

6

Ironstone, silty

4

Shale, silty

2

9

Shale, silty, with sporadic thin ironstone bands

3

3

Shale

5

0

G.D.G.

In the upper reaches of the Noe an R1c fauna with Reticuloceras davisi group and R. reticulatum was found in about 3 ft of shales with thin sandstones lying about 15 ft below the base of the Mam Tor Beds [SK 0925 8576], above Lee House. The whole of R1c within the Edale Shales is here more silty than the beds below, and thin sandstones are quite common, particularly as the Mam Tor Beds are approached; the thickness of these beds is about 15 ft. In Whitemoor Sitch, R1c faunas were not found though there is room for some 80 ft of beds of this zone within the Edale Shales. The expansion is explained by diachronism of the base of the Mam Tor Beds. I.P.S.

Alport and Ashop valleys

The Alport Borehole [SK 1360 9105], described by Hudson and Cotton (1943), provides the most complete single section of the Edale Shales in the district. The uppermost 129 ft or so of beds in the borehole also crop out nearby. A summary of the record with revised zonal boundaries and re-determination of certain fossils, is given below:

Thickness

Depth

feet

feet

Lower Reticuloceras zones (R1)

No core

100

100

Calcareous shale; H. henkei and R. circumplicatile group 108 ft to base

10

110

Homoceratoides prereticulatus, Homoceras undulatum and Hudsonoceras proteus zones (H2)

Shale with hard calcareous bands and bullion; Ht. aff. prereticulatus 110–112 ft; H. eostriolatum 116–127 ft; H. cf. undulatum, H. cf. smithii and Hd. proteus 127–139 ft

29

139

Homoceras beyrichianum and Homoceras subglobosum zones (H1)

Shales with hard calcareous bands and bullions; H. beyrichianum 190–196 ft; Homoceras sp. nov.196–199 ft; H. subglobosum 200–206 ft (and in bullions at 200 ft)

67

206

Nuculoceras nuculum Zone (E2c)

Shale and mudstone with hard calcareous siltstone bands;

E. bisulcatum and N. nuculum 216–222 ft; Cravenoceratoides fragilis, E. bisulcatum and N. nuculum 228231 ft; Ct. fragilis group, E. bisulcatum and N. nuculum [originally recorded as Ct. nititoides, now equated with lowest N. nuculum horizon (see Ramsbottom, Rhys and Smith 1962, p. 130)] 250–253 ft; P. aff. vetusta and N. stellarum 294–295 ft

89

295

Cravenoceratoides nitidus Zone (E2b)

Shale and mudstone, with numerous thin calcareous siltstone and cherty limestone beds to 306 ft; productoids, chonetoids, athyroids, Ct. nititoides, E. rostratum and trilobites 301–306 ft. Shales with cal- careous siltstones to 360 ft; Cravenoceras sp. 312–314 ft and Ct. edalensis 354–360 ft

65

360

Eumorphoceras bisulcatum Zone (E2a)

Platy pyritous shale and mudstone with calcareous siltstone bands to 449 ft, argillaceous limestones with thin shale partings to 463 ft; calcareous mudstones with thin limestones at top to 476 ft; E. bisulcatum 367–371 ft; E. bisulcatum and Kazakhoceras scaliger 399–408 ft; Chaenocardiola footii, Cravenoceras cowlingense and E. bisulcatum s.l. 453–476 ft

116

476

Cravenoceras malhamense Zone (E1c)

Silty shale with calcareous siltstone bands to 503 ft; calcareous mudstone with thin silty limestone bands to 533 ft; orthotetoid and productoid fragments, Actinopteria sp., Reticycloceras sp., C. malhamense, K. scaliger and Ceratiocaris sp. 503–533

ft

57

533

Eumorphoceras pseudobilingue Zone (E1b)

Silty shale at top, passing down into calcareous shale and mudstone with thin silty limestone bands; E. pseudobilingue 594–599 ft; E. sp. 660–662 ftEumorphoceras specimens from this level are poorly preserved, but may well belong to the Eia Zone. But see Trewin, Palaeontology, 13 (1970), p. 44. W.H.C.R.

130

663

Cravenoceras leion Zone (E1a)

Hard, calcareous, slightly silty and locally pyritous shale with abundant thin quartzose siltstone bands and sporadic thin silty limestone bands; bivalves, orthocone nautiloids, rare goniatites, mainly dimorphoceratids and plant debris to 1054 ft. [The "Alport Crowstones" of Hudson and Cotton (ibid., p. 168). Indications of faulting in core suggested that up to 75 ft of strata may have been repeated]. Shale and mudstone with calcareous and silty bands and thin silty limestone bands in the lower part, and containing Eumorphoceras medusa 1064 ft; C. leion and Lyrogoniatites cf. tonksi 1071 ft; Cravenoceras sp. and Eumorphoceras bisati 1072–1075 ft; Cravenoceras sp., E. cf. E. form A Moore, L. tonksi and Sudeticeras sp. 1075–1078 ft; C. leion early form and Girtyoceras cf. waitei Moore 1098–1099 ft. [The faunal list for the lower part of the E1a zone and the revised depth of the base of the Namurian in the borehole are based on Bisat (1950, p. 14)] 436

436

1099

Viséan (see p. 115).

The lowest Edale Shales at outcrop in the Alport and Ashop valleys are two small inliers of H2 beds. In the more northerly, an abandoned river bank [SK 1401 9029], 1010 yd S. 32°E. of Alport Castles Farm, has yielded Homoceras sp. in weathered shale 4 ft above the base. Hudson and Cotton (1943, p. 159) record H. smithii and Hd. proteus and 4 ft higher, H. cf. undulatum from this locality (Alport 16)Numbers preceded by the word 'Alport' indicate locality numbers of Hudson and Cotton (1943).. Nearly half a mile to the south, the southerly inlier is exposed in the east bank of the Alport [SK 1412 8969] east-north-east of Hayridge Farm:

feet

Shale, black with thin hard ferruginous bands; Aviculopecten sp., orthocone nautiloid, H. cf. henkei, cf. Homoceratoides varicatus and Reticuloceras sp. in top 2 ft; Posidonia sp. and Homoceras sp. (possibly the H. magistrorum band) in the bottom 2 ft

12

Shale, with thin hard ferruginous bands; Ht. prereticulatus 2 ft above base

16

The exact relationships in this exposure are somewhat complicated by contortion and minor faulting. It would appear to be the locality (Alport 13) from which Hudson and Cotton recorded H. cf. eostriolatum. Their record of H. eostriolatutn in bullions on the opposite side of the river (Alport 13a) has not been confirmed, probably due to the presence of a wall across part of the outcrop, but Caneyella sp., Dunbarella rhythmica and Anthracoceras or Dimorphoceras sp., suggestive of an R1a age, have been obtained from a nearby outcrop of shale [SK 1408 8965]. A few yards downstream [SK 1411 8963], Aviculopecten sp., Caneyella sp., Dunbarella sp., H. cf. henkei and Reticuloceras sp. (circumplicatile group) occur in shale. It is apparent that a change in the course of the river has altered the exact arrangement of outcrops since Hudson and Cotton examined them, and the lower horizons of H2 age have been largely obscured. In the east bank [SK 1415 8962] an exposure of shale contains Ht. cf. divaricatus, suggesting an upper R1a age. Shale, about 27 ft thick, now largely weathered, forms a roadside bank (Alport 1) [SK 1438 8951], near Gillethey Farm; the section (Bisat and Hudson 1943, p. 390) is as follows:

feet

Shale

Bullion bed; R. aff. pulchellum and variants, R. sp. nov.[crenulate form]

Shale

6

Bullion bed; R. aff. pulchellum and R. sp.

Shale

4

Shale with H. cf. henkei, Homoceratoides sp., R. cf. coronatum (Foord) and R. sp. nov.[non-crenulate form]

0.25

Shale

4

Shale, with H. henkei angustum Schmidt, H. sp. nov., Ht. varicatus group, R. sp.

0.25

Shale

5

Shale, about 45 ft thick, crops out between 100 yd and 200 yd south of this exposure in the east bank of the Ashop [SK 1438 8938]. Hudson and Cotton (1943, pp. 155–6) obtained from this exposure (Alport 3) an R1a fauna consisting of H. henkei, Ht. cf. varicatus and R. sp. cf. R. inconstans group from 6 ft above the base and a possible low R1b fauna from near the top of the exposed succession.

Adjacent to the more northerly inlier of H2 strata, in the west bank of the Alport [SK 1405 9012], 0.33 mile N.N.E. of Hayridge Farm, shale 10 ft thick contains Caneyella sp. [juv.], Dunbarella sp. and Anthracoceras or Dimorphoceras sp. in a band 4.5 ft above the base and R. cf. circumplicatile and R. cf. pulchellum in bullions 6 ft above the base. On the northern side of this inlier, Hudson and Cotton record an upper R1a fauna. This outcrop (Alport 17) [SK 1402 9035], 0.5 mile S.E. of Alport Castles Farm, has been extended by river action, but the older exposure is now partly obscured by alluvium, and the section, complicated by faulting, but suggestive of an R1b age, is:

feet

Shale, black; Ht. divaricatus and Hudsonoceras ornatum 7 ft above base; Reticuloceras sp. 9.5 ft above base

15

Shale; Promytilus sp. in upper 1 ft

18

About 0.25 mile farther south on the west bank [SK 1408 8998], and intermittently exposed for a further 170 yd downstream, are shales with soft black bands, rare ironstone bands and bullions, from two of which (Alport 14, 15) Hudson and Cotton obtained Hd. ornatum. An almost fully exposed sequence of upper R1b and R1c, strata up to the base of the Mam Tor Beds is present in the lower reaches of Swint Clough (Alport 20–22) for a distance of about 200 yd upstream from a point [SK 1347 9106) some 50 yd west of Alport Castles Farm. Bisat and Hudson (1943, p. 389) recorded:

feet

Shale

13

Shale; R. reticulatum s.s.

0.5

Shale, sparsely fossiliferous

12

Shale; Hudsonoceras ornatum, R. aff. moorei, Reticuloceras cf. regularum Bisat and Hudson, R. cf. stubblefieldi

1

Shale, sparsely fossiliferous

15

Bullion band; Homoceras striolatum early form, R. sp

Shale

13

Shale; Dunbarella sp.

0.5

Shale

8

Bullion band; Homoceras spiraloidesBisat and Hudson, H. striolatum early form, R. nodosum

Shale

6

In the Ashop valley, about 35 ft of shale with thin ironstone bands in the upper part underlies Mam Tor Beds [SK 1410 8942], 170 yd S.S.W. of the junction of the Alport and Ashop rivers, and the same strata are exposed in a number of other outcrops in the south bank of the river downstream as far as

Rowlee Bridge. An exposure (Alport 8), 120 yd N. of this bridge on the north bank [SK 1495 8918], showing 27 ft of rather silty shale with thin silty ironstone bands, and containing Caneyella rugata, Dunbarella sp., indeterminate goniatites and mollusc spat from 12 ft above base, is recorded by Hudson and Cotton (1943, pp. 153–4) as being basal Mam Tor Beds, but in the absence of distinct sandstones, is here assigned to the Edale Shales.

Fulwood Holmes

Edale Shales occur along the River Noe north of Hope as a narrow inlier near Fulwood Holmes. The lowest exposed strata are from near the base of the H. subglobosum Zone; they crop out in the east bank of the river [SK 1666 8537], west-south-west of Harrop Farm:

feet

Shale

4

Shale, with ferruginous bands: a bullion band containing Posidoniella sp., Homoceras subglobosum and H. sp. at the top

9.5

Shale, with large bullions containing

H. subglobosum

1.5

Shale with Posidoniella sp.

3.5

H. subglobosum also occurs in shales with calcareous mudstone bands about 60 yd downstream in the same bank [SK 1662 8537], and also, together with Aviculopecten sp., in similar strata on the opposite bank farther upstream [SK 1662 8548]. About 100 yd farther upstream on the west bank [SK 1659 8554], 11 ft of shale with calcareous bullions contain Aviculopecten sp., Posidoniella sp., Reticycloceras sp. and H. beyrichianum. Shale with ferruginous bands and calcareous bullions containing poorly preserved Homoceras sp. is exposed in the east bank [SK 1662 8526] and may represent either the H. beyrichianum Zone or be of lowest H2 age.

The Hudsonoceras proteum–Homoceras smithii and Homoceras undulatum horizons have not been proved, but are probably present in river bank exposures 120 to 180 yd S. of Normans Farm and also 200 yd W. to W.N.W. of Fulwood Holmes. The highest H2 horizon, represented by Aviculopecten sp., Anthracoceras or Dimorphoceras sp., Ht. prereticulatus and fish debris, occurs in shales and bullions at the base of an outcrop in the east bank [SK 1670 8500]. At 150 yd farther south, in the east bank of the river [SK 1667 8487], 10 ft of shale with thin black mudstone bands contains D. rhythmica and Reticuloceras sp. of R. circumplicatile group in the lower beds.

The best outcrops of R1b strata are adjacent to the railway-bridge over the river near Normans Farm. In 7 ft of shale on the west bank [SK 1663 8569] south-west of the bridge, Caneyella ?, D. cf. rhythmica, Postdonia sp., Homoceras? and Reticuloceras sp. (with R1b affinities) occur, and in similar strata on both banks immediately north-east of the bridge, Hd. ornatum and Reticuloceras sp. (nodosum group) are present in the lowest beds.

The presence of R1c faunas has not been proved, but in the river banks [SK 1667 8585] at Normans Farm, are good exposures of silty shales and mudstones becoming increasingly silty upwards, and with thin ironstone bands concentrated into certain parts of the succession. This sequence is very similar to the strata of R1c age exposed in Crowden Brook and Swint Clough. G.D.G.

Hope valley

In the western part of the Hope valley the Edale Shales form a broad tract on the northern side. Much of the outcrop is concealed beneath head, and exposures are for the most part confined to the banks of Peakshole Water and smaller streams.

The Castleton Borehole [SK 1410 8293] proved the following section of the lowest part of the Edale Shales, resting on shales of P2 age:

<>

Thickness

Depth

feet

inches

feet

inches

Head

15

0

15

0

Cravenoceras malhamense Zone (E1c)

Mudstone (little recovered)

1

6

16

6

Mudstone, grey, soft and fissile

4

2

20

8

Mudstone, hard silty calcareous to 22 ft, hard brownish below; Caneyella membranacea, C. cf. membranacea, Posidonia cf. corrugata and dimorphoceratid indet. [bilobate growth-lines] at 20 ft 9 in to 23 ft 4 in; C. membranacea and Cravenoceras malhamense at 23 ft 9 in ; C. membranacea, P. cf. corrugata and Rayonnoceras sp. at 24 ft 1 in to 24 ft 10 in

4

2

24

10

Mudstone, hard slightly silty; Caneyella membranacea, C. cf. membranacea, P. cf. corrugata, Cravenoceras ma!hamense, C. cf. ,nalhamense, dimorphoceratid indet. [bilobate growth-lines], fish debris indet.

4

8

29

6

Eumorphoceras pseudobilingue Zone (E1b)

Mudstone, soft grey; pyritous with fucoid markings below 35 ft; scales of Elonichthys sp., Rhadinichthys sp., palaeoniscids indet., Rhabdoderma?

20

6

50

0

Mudstone, grey silty, slightly calcareous; P. cf. corrugata, P. ? and fish debris in phosphatic nodules 50 ft to 50 ft 9 in; sponge spicules, P. cf. corrugata, dimorphoceratid [bilobate growth-lines], Eumorphoceras pseudobilingue, E. pseudobilingue C, Rhadinichthys sp. 51 ft to 54 ft 10 in

4

10

54

10

Mudstone, grey, with guilielmites (cores broken) to 58 ft, silty below; C. aff. membranacea, P. aff. corrugata, goniatite indet., fish indet. 56 ft to 60 ft 3 in; P. cf. corrugata, Kazakhoceras ? [with nodose venter] 61 ft to 62 ft 3 in

8

2

63

0

Cravenoceras leion Zone (E1a)

Mudstone, grey slightly bituminous with fish debris; slightly more silty below 72 ft; calcareous and silty below 86 ft 6 in; Edestodus sp. nov. at 65 ft; P. cf. corrugata, P. sp., crinoid columnals, Rhadinichthys sp. [scale], indet. palaeoniscid scale at 68 ft 6 in to 88 ft 6in

26

0

89

0

Mudstone, calcareous and bituminous; P. cf. corrugata, P. sp., dimorphoceratid, indet., goniatites and palaeoniscid scales 89 ft to 94 ft 9 in; P. sp. and Cravenoceras sp. 95 ft 6 in; P. cf. corrugata, P. sp., Cravenoceras leion, C. cf. leion, dimorphoceratid indet. [bilobate growth-lines], Eumorphoceras sp. 97 ft 6 in to 98 ft 7 in

9

7

98

7

Siltstone

11

99

6

Mudstone, dark; Caneyella membranacea, Cravenoceras cf. leion

1

99

7

Viséan (see p. 111).

The thinning of the lower zones adjacent to the limestone massif is very apparent in this section, E1a and E1b being together only 70 ft thick, as compared with 285 ft at Edale.

The Hope Cement Works Borehole (Fearnsides and Templeman 1932, pp. 100–5) provides the most complete section of the lower part of the Edale Shales in the Hope area. The site was at Salter BarnDemolished, now part of cement works. approximate ref. [SK 1678 8228], and the hole, after passing through 16 ft of head, proved beds referred to the Edale Shales to 280 ft overlying Lower Carboniferous rocks (see p. 113). There was a 2.5-ft bed of limestone at 98.5 ft and several thinner calcareous bands were noted. The fossils from the borehole, collected by A. Templeman, have been re-examined with the following results:

Nuculoceras nuculum Zone (E2c)

16 to about 26 ft: Mudstone, no core; these beds have been placed in E2c on account of the position of the underlying Ct. nititoides fauna which bears a fairly constant relation to the N. stellarum band.

Cravenoceratoides nitidus Zone (E2b)

About 26 to 77 ft: Mudstone, no core to 38 ft; mudstone, calcareous and platy shale; Cravenoceratoides nititoides at 38.5 ft; Leiopteria longirostris, orthocone nautiloid at 39 ft; Mitorthoceras? at 43 ft; Posidonia corrugata gigantea, Cravenoceras cf. holmesi, Cravenoceratoides cf. nitidus, Eumorphoceras sp. at 50 ft; P. corrugata, Streblochondria ? at 55 ft; P. corrugata, P. corrugata elongata Yates, orthocone nautiloid, Anthracoceras glabrum Bisat at 58 ft; P. corrugata elongata, Anthracoceras ? at 75 ft; A. cf. glabrum at 76 ft; Posidoniella aff. vetusta group at 77 ft.

Eumorphoceras bisulcatum Zone (E2a)

77 to 125 ft: Mudstone, as above to 115 ft; platy shale below; Eumorphoceras sp., fish debris at 86 ft; Anthracoceras? at 88 ft; Posidoniella aff. vetusta group, orthocone nautiloid at 92 ft; Leiopteria longirostris, Posidoniella aff. vetusta group, goniatite indet. at 101 ft 6 in; Eumorphoceras bisulcatum, Kazakhoceras scaliger at 111 to 114 ft; fish debris at 125 ft.

Cravenoceras malhamense Zone (E1c)

125 to 211 ft: Mudstone with a 3-ft calcareous bed at 168 ft and "an earthy bituminous calcareous group" with thin limestones between 195 and 210 ft; fish debris at 180 ft; Anthracoceras or Dimorphoceras sp. at 195 ft; A. or D. sp. at 202 ft; Cravenoceras malhamense, D. sp., Kazakhoceras scaliger at 203.75 to 209 ft; Posidonia sp. at 211 ft.

Eumorphoceras pseudobilingue Zone (E1b)

211 to about 238 ft: Shale with 9 ft of "hard, rather sandy ferruginous mudstone" at 237 ft; fish debris at 220 ft; P. corrugata, Anthracoceras or Dimorphoceras sp. at 230 ft; Kazakhoceras? at 237 ft.

Cravenoceras leion Zone (E1a)

About 238 to 280 ft: Mudstone, hard calcareous and bituminous below 276 ft; Posidonia? at 274 ft; fish debris at 275 ft; Obliquipecten costatus, Catastroboceras cf. quadratum (Fleming), Cravenoceras leion, Eumorphoceras sp. at 277 to 280 ft. These beds are underlain by shales of P2 age (see p. 112).

The borehole showed little in the way of silty beds at the horizon of the 'Crowstones' in the E1a Zone of the Alport Borehole. The flaggy limestones developed in the E1b Zone in both the Edale and Alport boreholes were not present, though those at the Cravenoceras malhamense horizon (E1c) were.

The lowest beds of the Edale Shales are seldom exposed, though an excavation at Messrs. Earle's Hope Cement Works [SK 1658 8221] showed dark shale dipping steeply north-eastwards, and some 15 yd away from the Carboniferous Limestone. The exposure must lie close to the position of the trench at the entrance to Nun Low Quarry, which Jackson (1925, pp. 271–2) described as showing shale resting on "an irregular and channelled surface of limestone". Jackson further noted that "pockets and fissures of the limestone are also filled with shale". I.P.S.

To the south-east of Hope, strata of R1b age were proved in temporary excavations at the sewerage works. Bullions containing Reticuloceras cf. nodosum and R. stubblefieldi occurred in shale at a depth of 12 to 15 ft [SK 1764 8317]. A few yards farther west Posidonia obliquata (Brown) and Reticuloceras sp., found in shale at a depth of 12 to 15 ft [SK 1759 8319], are either of high R1b or low R1c age.

No surface outcrops containing R1b or earlier faunas have been proved in the vicinity of Hope. In the west bank of the Noe [SK 1751 8344], 300 yd E. of Hope church, shale 2 ft thick contains Caneyella squamula, Dunbarella rhythmica, ? P. obliquata and Anthracoceras or Dimorphoceras sp. in a ferruginous horizon near the top of the outcrop, and may be of high R1b or R1c age. At a point 80 yd upstream on the east bank [SK 1747 8350], shale 5 ft thick contains C. squamula, D. rhythmica, Anthracoceras or Dimorphoceras sp., Homoceras sp., Homoceratoides sp. [juv.] and Reticuloceras sp., indicating a probable R1c age.

A number of outcrops of silty shale with ironstone bands, typical of the highest Edale Shales, are present farther upstream as far as Killhill, and similar strata are exposed in the south bank of the Noe a few yards east of the confluence with Peakshole Water. G.D.G.

In Peakshole Water the following section of beds of probable R1c age was measured on the right bank [SK 1666 8215], 0.25 mile S.E. of Marsh Farm:

feet

Shale, soft dark, ferruginous in places; Dunbarella sp. [juv.], Posidonia sp. and Homoceratoides divaricatus 3 ft from base; Caneyella sp., Dunbarella sp., Homoceras striolatum and Reticuloceras sp. 9 ft from base

15

Shale, ferruginous, with bullions

2 ft to 3.25

Shale, soft black seen

12

Another section, 25 yd downstream and on the left bank, yielded Anthracoceras or Dimorphoceras sp. and Hudsonoceras ornatum.

At The Folly, a number of shallow boreholes, put down by Messrs. Earle to prove shale reserves for the Cement Works, have penetrated the upper part of the Edale Shales. One of these (No. S5) [SK 1717 8295] passed through Mam Tor Beds to 82.75 ft, and Edale Shales to 160 ft: the latter consisted of silty and finely micaceous mudstones with sporadic thin sandstone bands (one 2 ft thick occurred at 105.5 ft). The borehole yielded the following fossils: 113 ft 5 in to 123 ft 9 in, Caneyella cf. rugata, Dunbarella rhythmica, Posidonia obliquata, Promytilus sp., Anthracoceras or Dimorphoceras sp., Reticuloceras sp. ; 125 ft to 145 ft 5 in, Caneyella cf. squamula, P. obliquata, Anthracoceras or Dimorphoceras sp., Reticuloceras cf. reticulatum; 146 ft to 152 ft, Caneyella sp., Dunbarella sp., Posidonia sp. nov., palaeoniscid scales; 153 ft 6 in to 156 ft 5 in, C. squamula, D. rhythmica, Anthracoceras or Dimorphoceras sp., Reticuloceras spp.[includes ? R. nodosum group]. The faunas indicate an R1c age for most of the beds passed through, though R1b may have been reached at the base.

Mam Tor

In the vicinity of Mam Tor the unconformity between Millstone Grit and Carboniferous Limestone is at its most acute. The outcrop of the Carboniferous Limestone here forms a marked salient into the Millstone Grit (see also p. 162). As the junction of the two formations is traced northwards from near the Castleton Borehole (see p. 199), where C. felon and shales of P2 age are present, progressively higher horizons in the shale are found to rest on the Carboniferous Limestone. The mapping shows the surface of the limestone to be very irregular.

An exposure in the upper part of Odin Sitch [SK 1329 8351], showed the following section some 3 ft above the Carboniferous Limestone:

feet

Shale, dark grey

Mudstone, hard calcareous; fossiliferous crinoidal limestone debrisFossils include Lithostrotion cf. martini Milne Edwards and Haime, Syringopora ?, Martina?, productoid fragments, Rugosochonetes sp.

5

Limestone, dark, thin-bedded towards top; ?Posidonia corrugata

3

The dark limestone is probably that stated by Hudson and Cotton (1945, p. 13) to contain in addition Posidoniella sp., Syncyclonema carboniferum Hind and Eumorphoceras bisulcatum; it was considered that "the age of the fauna was certainly E2b". It should be noted that this is one of the few localities at or near the unconformity which shows derived material in the Edale Shales.

The only section of Edale Shales in situThis was described by Jackson (1927, pp. 23–4) as the upper of three slipped masses within the landslip. The main features of the fauna were recognized. in the landslip-scar at Mam Tor is [SK 1299 8346] some 300 yd S.E. of the summit. The sectionIncluding information from Messrs. W. E. Graham and J. Pattison. commences some 30 ft below the base of the Mam Tor Beds, though a small fault down-throwing to the north may cut out about 10 ft of shale:

feet

inches

Shale, silty with thin sandstone bands, becoming more numerous towards top

about 7

0

Shale, weathered, with poorly preserved fossils; Dunbarella rhythmica, orthocone nautiloid indet., Dimorphoceras sp., mollusc spat

5

0

Ironstone

2 in to 7

Shale; Posidonia sp. [elongate form], Reticuloceras cf. moorei, R. sp. (R. nodosum group)

5

0

Shale, black: Posidonia cf. obliquata, Homoceratoides aff. divaricatus, Reticuloceras sp.

6

Ironstone; Dimorpoceras sp., Hudsonoceras ornatum, Reticuloceras sp.

2 in to 7

Shale; Caneyella squamula [elongate form], Dunbarella rhythmica, Dimorphoceras sp., Homoceras sp., Homoceratoides sp. [juv] [divaricatus group]

11

6

Shale, 'sulphurous'; Dimorphoceras sp., Reticuloceras cf. nodosum

2

6

Ironstone; Caneyella sp., Homoceras sp., R. cf. nodosum

1 in to 7

Shale, 'sulphurous', Dunbarella sp., orthocone nautiloid, Dimorphoceras sp., Reticuloceras sp. (nodosum group)

3

6

Shale, dark platy

10

Ironstone; Caneyella sp., D. rhythmica

0 to 3

Shale, 'sulphurous'; indet. goniatites, fish fragments

2

6

Ironstone

0 to 2

Shale, platy 'sulphurous'

9

9

Shale, pale 'sulphurous' in top 2 ft 8 in; darker below with ferruginous patches; C. squamula, D. rhythmica, Dimorphoceras sp., Reticuloceras sp.

3

6

Ironstone; Hd. ornatum, Reticuloceras sp.

2 in to 4

Mudstone, ferruginous at top; Dunbarella sp., Dimorphoceras sp., Homoceras sp., Reticuloceras sp.

1

9

Shale, soft pale 'sulphurous'

5

0

Shale, platy; Dunbarella sp.

2

Shale, grey 'sulphurous'

10

The whole of the section, with the possible exception of the lowest 6 ft which contains no diagnostic fauna, is referred to the R1b Zone; the base of R1c probably lies just above the topmost beds. The base of the section is estimated to lie about 330 ft above the Carboniferous Limestone, giving a total thickness for the Edale Shales of some 400 ft. Near the limestone boundary the Edale Shales appear to have thinned further. The presence of E2b faunas as noted above in Odin Sitch, in an area where the general tendency is for thinning towards the limestone massif, suggests a figure of as little as 300 ft for the Edale Shales here.

The presence of lower faunas than the above within the Mam Tor landslip was recognized by Jackson (ibid., p. 24) and confirmed during the present work in two places:

2. [SK 1305 8349]. Probably the "middle block" of slipped material of Jackson. This shows approximately 44 ft of shale with Reticuloceras circumplicatile at the top, Homoceras cf. magistrorum at 12 ft from the top and Hudsonoceras proteus at the base. This has apparently moved very little.

1. [SK 1315 8345]. Probably at or near the position of the "lower block" of Jackson. This yielded only indeterminate dimorphoceratids and Posidonia cf. corrugata during the present work, though Jackson records Eumorphoceras bisulcatum and Nuculoceras nuculum. The present stratigraphical position of this locality is about 180 ft above the Carboniferous Limestone.

Between the Blue John Mine [SK 1317 8319] and Windy Knoll [SK 126 830] the shale occupies an irregular erosional hollow on the limestone surface. A small inlier of limestone occurs within the shale east of the road junction [SK 129 831]; the sides of the inlier are steep and it protrudes through the shale, forming a small hill.

Hudson and Cotton (1945, p. 14) record Reticuloceras from a pocket of shale on the limestone surface, presumably in the vicinity of Windy Knoll. This is unfortunately not accurately located and the record has not been confirmed during the present work. The occurrence of Reticuloceras in this position is difficult to reconcile with the stratigraphy, and it is suggested that the shale may not have been in situ.

Perryfoot valley

Between Sparrow Pit and Windy Knoll the outcrop of the Edale Shales occupies a broad valley between the escarpment of Rushup Edge and the Carboniferous Limestone. Much of the ground is obscured by head, though streams cut through this in places. The junction of shale and limestone is marked by a line of swallow-holes.

Hudson and Cotton (ibid., p. 13) described the faunas from a series of tips from shafts along the line of an old sough driven northwards from the limestone boundary near Peakshill. Their results were:

  1. Northern tip [SK 1175 8307]; Homoceras sp. and Homoceratoides varicatus [or Ht. prereticulatus].
  2. Tip [SK 1173 8303] 50 yd S.23°W. of (a): Homoceras henkei, H. henkei angustum, H. striolatum group, Reticuloceras inconstans and R. pulchellum.
  3. Tip [SK 1172 8295] 85 yd S.8°W. of (b): Homoceras sp. cf. H. eostriolatum towards H. henkei.

These faunas indicate a low R1 horizon and Hudson and Cotton were of the opinion that the beds resting on the limestone here were of high H2 age, the total thickness of Edale Shales being here some 150 to 200 ft. However, this figure seems most unlikely in view of the present estimate of 400 ft at Mam Tor (see p. 202), where the thickness would be expected to be less than at the present locality. There is no evidence that any of the shafts reached Carboniferous Limestone.

The limestone-shale junction is exposed in several sink-holes in the valley bottom, one [SK 1027 8161], north-north-east of Perryfoot showing the following section:

feet

Head

5

Shale, soft grey

10

Shale, dark hard platy

18

Shale, soft grey

1

Not exposed

3

Shale, grey

2

Not exposed

4

Shale, grey, with blocks of dark limestone up to 6 in diameter (dip at base roughly follows unconformity)

3.5

Unconformity

Limestone, massive fossiliferous (fore reef)

about 10

Near Tor Top, Perryfoot approximately [SK 0985 8130], Jackson (1925, p. 270) recorded "black shales and limestones dipping N.W. off massive limestones Higher in the shales are thinly-bedded black limestones containing crinoid-stems, goniatites (especially Eumorphoceras bisukatum), nautiloids, etc. These are probably not more than 75 feet above the junction."

Higher beds than the above are exposed in a stream [SK 0986 8170], north of Perryfoot, where hard dark calcareous flags yielded cf. Cravenoceras darwenense Moore, Eumorphoceras sp., Nuculoceras nuculum, N. cf. tenuistriatum Demanet (E2c Zone). Some 160 yd farther upstream an exposure showed 10 ft of soft grey 'sulphurous' shale with a 2.5-in band containing unidentifiable goniatites at 4.5 ft from base.

To the west of Perryfoot, records in Coalpithole Mine show 216 ft of shale on limestone in No. 8 Shaft [SK 0957 8119] and 424 ft of shale on limestone in No. 10 Shaft [SK 0915 8129]. The latter starts some 75 ft below the base of the Shale Grit giving an approximate thickness of 500 ft for the shale at this locality.

Sparrow Pit and Barmoor Clough

At Sparrow Pit some 350 ft of shale separate the Shale Grit and Carboniferous Limestone. The shale is mostly ill exposed. At Barmoor Clough approximate site [SK 078 796], close beneath the Shale Grit, Jackson (1927, p. 31) recorded shale with "Reticuloceras reticulation, Homoceras striolatum and Pterinopecten rhythmicus".

Dove Holes

The most complete section in this area is provided by the railway-cuttings north of Dove Holes, starting at the tunnel entrance [SK 0761 7933] and with the bottom of the section [SK 0770 7901], 240 yd to the south:

feet

inches

To base of Shale Grit

100

0

Shale, dark grey weathered; Caneyella sp., Dunbarella rhythmica, Posidonia sp.,'Stroboceras' sp., Dimorphoceras, Homoceras cf. striolatum, Hudsonoceras ornatum, Reticuloceras sp. (R. nodosum group), mollusc spat

14

0

Shale, soft black decalcified; Dunbarella sp., Reticuloceras sp.

4 in to 5

Shale, blue grey, weathered; Caneyella sp., D. rhythmica, R. cf. nodosum, R. cf. subreticulatum; 2.5-ft bed of bullion, at 2.5 ft from base, with R. cf. nodosum and R. cf. pulchellum

18

0

Ironstone

2 in to 4

Shale, dark grey, poorly exposed

12

0

Not exposed about

25

0

Shale, dark grey; Caneyella sp. [juv], Promytilus sp.

33

0

Bullion; Homoceras subglobosum (base of H1a Zone)

up to 6

Shale, grey

11

0

Shale, hard ferruginous; Posidoniella sp.

6

Shale, grey, very weathered

1

6

Shale, dark decalcified; Posidonia corrugata, Posidoniella variabilis, Dimorphoceras sp., Eumorphoceras bisulcatum, Nuculoceras nuculum

4

Shale, hard ferruginous; Eumorphoceras bisulcatum

6

Shale, dark grey

2

6

Ironstone; P. corrugata and goniatites indet.

6

Shale, grey

12

0

Ironstone band, impersistent ; P. corrugata

8

Shale

3

0

To Carboniferous Limestone

about 90

0

This gives a total thickness of about 325 ft for the Edale Shales at this locality.

Near Dove Holes the section of the main line railway tunnel shows some 300 ft of shale to be present, though these beds thicken southwards to 500 ft between Turner Lodge and Brook House.

From Dove Holes to a point some 0.5 mile N. of Brook House, the limestone-shale junction appears to be regular; farther south the shale rests on a strongly eroded limestone surface, filling well-marked valleys, respectively 500 yd N. and 200 yd S. of Brook House. A small outlier of shale is present on the level upper surface of the limestone at a point 700 yd N.E. of Brook House.

The shales are exposed in several places in a stream just south of Dove Holes; an exposure [SK 0730 7772] here showed dark decalcified shale 1 ft 6 in, grey 'sulphurous' shale about 4 ft, soft decalcified shale with Posidoniella sp., Anthracoceras or Dimorphoceras sp. and Cravenoceratoides or Cravenoceras sp. 7 in, hard dark grey shale 1 ft 3 in, obscured 3 ft, on soft grey shale 2 ft. The horizon is probably near the top of E2. Exposures of the shales are fairly continuous for some 320 yd upstream from the above locality, but no fossils were found.

Beds near the junction with the limestone are well seen in Nun Brook. An exposure [SK 0663 7485], south-west of Brook House, yielded Posidonia corrugata, Posidoniella variabilis, Spirorbis sp. on carbonized plant fragment, Anthracoceras sp., Dimorphoceras?; this probably indicates an E2 horizon.

Downstream, the following section is exposed [SK 0655 7469]:

feet

inches

Shale, grey 'sulphurous' with a 3-in dark decalcified band in middle

4

0

Shale, dark decalcified with a 10-in bullion

1

9

Shale, contorted and sheared, base clear-cut

6

0

Shale, soft 'mushy'

1 in to 2

Shale, grey, with 1-in band at base with Posidonia corrugata, Posidoniella variabilis, Anthracoceras sp. and an orthocone nautiloid

2

1

Shale, hard platy

1

6

Shale, 'sulphurous'

3

0

This fauna is considered to be probably E2 and most likely one of the Anthracoceras bands in E2b.

Todd Brook valley

Beds underlying the Kinderscout Grit are present along the axis of the Todd Brook Anticline between Kettleshulme and Eaves Farm, near the southern boundary of the district. To the north of Green Booth the Edale Shales are, with few exceptions, obscured by boulder clay. Between this locality and Redmoor Farm, however, shales with thick sandstones of 'crowstone' type are exposed in a strongly-folded belt. Typical sections are provided by a quarry [SJ 9819 7651] on the southern side of Fox Hill:

feet

inches

Shale, grey about

6

0

Sandstone, irregularly bedded massive siliceous

12

0

Shale with lenses of sandstone up to 6 in thick

3

0

Sandstone, siliceous, in beds up to 6 in thick with shale partings

1

9

A larger working [SJ 9815 7590] 0.25 mile S.W. of Saltersford Hall showed:

feet

inches

Sandstone, siliceous, in beds up to 2 ft thick

5

6

Shale parting, poorly exposed, about

4

Sandstone, coarse massive siliceous

4

4

Shale, with thin siltstone bands

0 to 5

Sandstone, fine-grained flaggy siliceous

6

Sandstone, pale violet siliceous

4

4

Shale

0 to 1

Sandstone, hard siliceous, with a 3-in shale parting in middle

7

1

Shale, pale-weathered grey

4

0

Veins of baryte are present in the sandstones in the latter exposure (see p. 317),

The only evidence of horizon of the shales in this area is provided by an exposure [SJ 9813 7636], on the left bank of Todd Brook, near Saltersford Hall: dark decalcified shale with Posidonia corrugata, Dimorphoceras sp., Eumorphoceras bisulcatum s.l. and Nuculoceras nuculum 6 ft 6 in, on dark decalcified shale with bands of siliceous sandstone up to 3 in thick 3 ft 3 in, on soft grey shale 3 ft. This exposure, indicative of an E2c horizon, cannot, owing to folding and possible faulting, be accurately related to the beds with 'crowstones' of Fox Hill, though it appears certain that the ages of the two cannot differ greatly. It seems likely that most of the exposed 'crowstones' are slightly younger in age than the N. nuculum band, but do not extend far up in the succession, and are all referred to the E2 stage. I.P.S.

Derwent valley

The highest beds of the Edale Shales crop out near Hathersage and also near the submerged village of Derwent, in Ladybower Reservoir. In the west bank of Hood Brook [SK 2286 8121], 250 yd N.E. of Nether Hall, 16 ft of rather silty shale with small ferruginous nodules, containing Caneyella ?, Dunbarella sp. Posidoniella sp., Homoceras sp. and Reticuloceras cf. reticulatum are exposed. Similar fossiliferous strata are present in the banks of the same stream about 10 to 20 yd above its confluence with the Derwent. The intervening exposures along the stream are of typical basal Mam Tor Beds, and it appears that the two exposures mentioned are parts of a small upfaulted mass of Edale Shales, the remainder of which is obscured by Drift.

In 1959 the level of Ladybower Reservoir was sufficiently low to expose the remains of Derwent village and parts of the original channel of the river, including a number of outcrops of lower and basal Mam Tor Beds. These beds were seen, in the cores of 'valley bulge' folds [SK 1819 8858], to be underlain by dark silty shales with thin ironstone bands identical in lithology to the highest Edale Shales to the west and south. G.D.G.

Bradwell and Great Hucklow

With the disappearance of the Mam Tor Beds and some lateral passage of the Shale Grit into the underlying shales in this area, the Edale Shales south of Bradwell may include a small thickness of beds higher than in the type area, though with the general southeasterly thinning, this rapidly loses its significance. These beds consist of shales, some 550 ft in thickness and somewhat silty, and with thin sandstone bands towards the top. The greater part is ill exposed.

The unconformity at the junction with the Carboniferous Limestone is in places very irregular. At Bradwell Hills this is particularly so, and appears to be due to the original depositional form of the flat reef in the Eyam Group, further modified by pre- or early Namurian erosion. Thus, about 500 yd S. of St. Barnabas's Church, Bradwell, a narrow valley in the limestone appears to be filled by shale. The records of shale with Eumorphoceras bisulcatum noted by Jackson (1925, pp. 273–4) in this vicinity have been confirmed just west of the small brook 500 yd S. of St. Bamabas's Church. The shales at this locality [SK 1757 8063], and for a distance of 90 yd upstream, yield Aviculopecten sp., Chaenocardiola ?, Posidonia corrugata, P. corrugata gigantea, Dimorphoceras sp. and Eumorphoceras bisukatum erinense Yates, indicative of an E2a horizon.

From the tips of Wortley Mine [SK 1774 8105], near Bradwell church, Jackson (1927, p. 31) recorded a fauna, considered by him to be the same horizon as that from Bradwell Hills, which included E. bisulcatum and Kazakhoceras scaliger (recorded as "goniatite with lattice ornament").

To the south and south-east of Bradwell Hills the unconformable junction with the Carboniferous Limestone is much more regular than in the Castleton–Bradwell area, and in most places the mapping suggests that there is little or no angular discordance between the two formations.

A number of shafts, to workings on the Hucklow Edge Vein, have penetrated the shales south of Hucklow Edge. The greatest thickness was passed through at Silence Mine [SK 1880 7799] which, starting about 75 ft below the base of the Shale Grit, proved 328 ft of shale before reaching limestone.

A sink-hole [SK 1868 7746], 0.5 mile N.W. of Foolow, shows beds low in the shale sequence: dark shale 6.5 ft, not exposed 9 ft, on grey to dark grey thin-bedded cherty limestone (Eyam Limestones) 9 ft.

The Hucklow Edge No. 1 Borehole [SK 1941 7781], west of Bretton, proved a nearly complete section of the Edale Shales. This is summarized below:

Thickness

Depth

feet

inches

feet

inches

Reticuloceras circumplicatile Zone (R1a)

Mudstone with some hard calcareous bands; R. cf. todmordenense at 27 ft 6 in; Homoceras henkei at 32 ft 4 in; H. magistrorum band 3 ft 4 in at 38 ft 4 in.

38

4

38

4

Homoceratoides prereticulatus, Homoceras undulatum and Hudsonoceras proteus zones (H2)

Mudstone; Homoceratoides prereticulatus band 7 in at 39 ft 8 in and Hudsonoceras proteus band 1 ft 1 in at 50 ft

11

8

50

0

Homoceras beyrichianum and H. subglobosum zones (H1)

Mudstone with a 5-in silty band at 51 ft 4 in; fucoid markings at 54 ft 3 in; thin pyrite lens at 70 ft 9 in; probable H. beyrichianum band 1 ft 7 in at 64 ft; several horizons with H. subglobosum between 67 ft 1 in and 77 ft 1 in

27

1

77

1

Nuculoceras nuculum (E2c) and Cravenoceratoides nitidus (E2b) zones

Mudstone with a 5-in argillaceous limestone at 112 ft; 3-in band with sphaerosiderite at at 113 ft 3 in; 19-in hard calcareous band at base; upper N. nuculum band 7 in at 87 ft 1 in; middle N. nuculum band 1 ft 4 in at 99 ft 2 in; lower N. nuculum band 2 ft 6 in at 111 ft 9 in; Cravenoceratoides nititoides band 9 in at 132 ft 3 in; Ct. nitidus band 4 in at at 135 ft 5 in; Ct. edalensis in 10 in at 150 ft 4 in; Cravenoceras subplicatum in 1 ft 0.5 in at 151 ft 5 in

74

4

151

5

Eumorphoceras bisulcatum (E2a) Zone

Mudstone with a 2.5-in fine-grained limestone at 164 ft 2.5 in; E. bisulcatum band 5 ft at 165 ft; Cravenoceras cowlingense band 1 ft 9 in at 171 ft 9 in

20

4

171

9

Cravenoceras malhamense (E1c) Zone

Mudstone; C. malhamense band at 173 ft 1 in

1

4

173

1

Eumorphoceras pseudobilingue (E1b) Zone

Mudstone; E. pseudobilingue band 3 in at 177 ft 1 in

4

0

177

1

Cravenoceras leion (E1a) Zone

Mudstone with a 6-in fine-grained limestone at 178 ft; C. leion band 7 in at 179 ft 2 in

2

1

179

2

Viséan (see Appendix 1, p. 370)

The great condensation of the E1 strata is a striking feature of this section (see (Plate 15)).

The Hucklow Edge No. 2 Borehole [SK 2025 7760] (see Appendix 1, pp. 371–2) proved the following succession:

Thickness

Depth

feet

inches

feet

inches

No core

207

9

207

9

Cravenoceratoides nitidus (E2b) Zone

Mudstone, with a 1-ft limestone band at 219 ft; Ct. nititoides band 1 ft 2 in at 212 ft 6 in; Ct. edalensis band 7 in at 236 ft

35

10

243

7

Eumorphoceras bisulcatum (E2a) Zone

Mudstone with thin limestone bands, 1.5 in at 251 ft 2.5 in, 5 in at 252 ft 9 in and 3 in at 253 ft 3 in; Leiopteria longirostris at 243 ft 11 in; E. bisulcatum band 4 ft 9 in at 251 ft 11 in

21

11

265

6

Viséan (see p. 101, etc.)

This borehole shows a similar development of the pre-Namurian unconformity to the Bradwell Hills area and Mill Lane, Eyam.

Eyam, Stoney Middleton and Calver

To the north of Eyam the full thickness of shale was passed through at Ladywash Shaft [SK 2189 7754] between the base of the Shale Grit at 312 ft and the Carboniferous Limestone at 699 ft, a thickness of 387 ft. The Edale Shales have been met with in places in the mine workings. The recent driving of a crosscut between Stoke Sough and the Old Edge Vein provided evidence of the horizon of the lowest shales underground. Material from a few feet above the Carboniferous Limestone [SK 2253 7683], 1050 yd S. 42°E. of Ladywash Shaft, yielded P. corrugata, P. corrugata elongata, Cravenoceras cf. cowlingense, E. bisulcatum, crinoid debris and fish fragments. This indicates the main E. bisulcatum horizon in E2a. Material from some 160 yd farther down the crosscut [SK 2262 7693] and about 15 ft above the horizon of the last locality yielded the following fauna: P. corrugata, P. corrugata gigantea, orthocone nautiloids and Cravenoceratoides edalensis. The fauna is indicative of the Ct. edalensis band at the base of E2b.

Several sections in the shales occur in a stream north of Eyam. The lowest of these, about 170 ft above the Carboniferous Limestone [SK 2145 7695], east of Eyam View, showed 11 ft of dark shale with a 1-ft bed yielding Anthracoceras or Dimorphoceras sp. at 2.5 ft from the base. The fauna gives no indication of horizon. A higher section [SK 2142 7719] in the same stream is as follows:

feet

Base of Shale Grit

Sandstone and siltstone, interbedded

6

Mudstone, silty

7

Not exposed

12

Sandstone

8

Mudstone, silty and siltstone

17

Shale, dark pyritous in part

4

Mudstone, silty

4

Not exposed about

20

Shale, dark

25

Not exposed about

25

Shale, dark

6

Shale, dark, with marine fossils in top 1 ft and lowest 3 ft 6 in; Caneyella sp., Dunbarella sp., orthocone nautiloid, Dimorphoceras sp., Homoceras sp., Reticuloceras cf. reticulaturn, Cypridina sp.

7.33

The fossiliferous horizon is in high R1 and the section corresponds to that in the Edale valley where the R. reticulatum band lies close beneath the base of the Mam Tor Beds. Much of the beds between the R. reticulatum band and Shale Grit in the above section is, therefore, the lateral equivalent of the Mam Tor Beds.

To the south-east of Eyam, shale occupies an erosional valley in the P2 flat-reef limestones near Cliffstile Mine [SK 2246 7595]. Nearby, in Mill Lane [SK 2236 7616] 1 ft 9 in of shale with thin bands of dark limestone yielded Obliquipecten sp., P. corrugata, 'Cyrtoceras' rugosum (Phillips non Fleming), 'Stroboceras' sp., Anthracoceras or Dimorphoceras sp., Eumorphoceras sp. and Coleolus?. From this locality Jackson (1927, p. 31) recorded Posidonomya sp., Pseudamussium cf. praetenuis (von Koenen), A. glabrum and E. bisulcatum; the record of E. bisulcatum affords clearer evidence of horizon (E2) than does the more recently collected fauna.

The shales thin in an easterly direction, only some 250 to 300 ft being present at Stoney Middleton. Between the latter place and Coombs Dale, shales occupy a broad depression eroded in the dip-slope of the Carboniferous Limestone. Part of the shale outcrop is obscured by boulder clay (see p. 342). The best exposure lies in a landslip-scar [SK 2296 7525] south-west of Stoney Middleton church where 2 ft of dark decalcified shale is seen. A little farther to the south-east, Morris (1929, p. 58) records "Posidonomya membranacea" and a few goniatites near Trinkey Lane, about 0.25 mile S.E. of Stoney Middleton.

Wardlow Mires outlier

Shale occupies a shallow depression some three quarters of a mile in length, with Wardlow Mires on its western edge. The presence of shales of P2 age has already been noted (see p. 105), though in view of their normal absence adjacent to the shelf area, the practice followed on the map has been to limit their outcrop as far as the scattered surface provings allow. Forefield Shaft [SK 1882 7577] at Watergrove Mine passed through 30 ft of shale before entering limestone; some at least of this shale is P2 in age.

The only surface evidence of horizon of the higher beds (E2) was obtained by Shirley and HorsfieldChief elements of faunas including E. bisulcatum listed, but no precise localities given. (1945, p. 293) from a trench crossing the outlier. The collections made were presented to the Geological Survey and details are as follows:

1.      [SK 1858 7547]: P. corrugata, Cravenoceras sp., E. bisulcatum s.s.

2.      [SK 1847 7549]: P. corrugata, smooth pectinoid indet., Cravenoceras sp., dimorphoceratid indet., E. bisulcatum.

3.      [SK 1839 7550]: P. corrugata, E. cf. bisulcatum.

An attempt to supplement the above information was made during the present work by digging at several points. The only locality yielding fossils was a bank [SK 1816 7568] 70 yd N.E. of Wardlow Mires, where P. corrugata, coiled nautiloid (Catastroboceras?) and indet. goniatites were found.

The Wardlow Mires No. 1 Borehole [SK 1850 7553] (see also p. 378), near the centre of the shale outlier, proved a very condensed sequence of Namurian shales with the following generalized section:

Thickness

Depth

feet

inches

feet

inches

Eumorphoceras bisulcaturn (E1a) Zone

Mudstone; E. bisulcatum horizon at 10 ft 1 in; Cravenoceras cowlingense horizon at 20 ft 9 in

20

9

20

9

Cravenoceras malhamense (E1c) Zone

Mudstone

10

21

7

Eumorphoceras pseudobilingue (E1b) Zone

Mudstone; E. pseudobilingue band at 29 ft 8.5 in

8

1.5

29

8.5

Cravenoceras leion (E1a) Zone

Mudstone; ?C. leion band 4 ft 3 in at base

38

0.5

67

9

Viséan shales (see p. 105)

The Wardlow Mires No. 2 Borehole [SK 1825 7586] (see Appendix 1, pp. 378–82) proved a comparable section, the C. leion band being confirmed in this case. I.P.S.

Mam Tor Beds

Alport and Ashop valleys

An inner of Mam Tor Beds is present in the Ashop valley between the Snake Inn and the western end of Ladybower Reservoir, extending up the Alport valley to approximately a mile north of Alport Castles Farm. Their thickness in the Ashop valley is over 200 ft but they thin northwards to 123 ft in Swint Clough, where nearly continuous exposures of thin-bedded sandstones and silty shales are present. In the south bank of Swint Clough [SK 1318 9106], 9 ft of shale and siltstone contain Dunbarella sp., Posidonia obliquata, Anthracoceras or Dimorphoceras sp., Homoceras? and Reticuloceras?. This outcrop (Alport 24), noted by Hudson and Cotton (1943, p. 154), is from the upper part of the Mam Tor Beds.

Good exposures of thin-bedded sandstone and silty shale occur in the banks of the Ashop, especially near the Snake Inn, south of Wood Houses and opposite the junction with the River Alport. An 18-in mass of sandstone, probably a slump-ball, is enclosed in silty shale on the west bank of Lady Clough [SK 1079 9091]. In the south bank of the Ashop [SK 1498 8905] 520 yd S.W. of Rowlee Farm, the basal Mam Tor Beds consist of silty shales and sandy siltstones with thin sandy ironstone bands 23 ft, with Caneyella ? and R. cf. reticulatum at 8.5 ft above, and Anthracoceras or Dimorphoceras sp. and Homoceras? at 13.5 ft above the base of the section. Farther east [SK 1541 8896], from about the middle of the Mam Tor Beds, Caneyella sp., Dunbarella sp., Posidonia sp. and Anthracoceras or Dimorphoceras sp. are present in thin silty shale alternating with siltstone and sandstone bands 32 ft. Hudson and Cotton (1943, p. 154) record R. cf. reticulatum s.s. from a locality (Alport 30) which lies near this outcrop.

Derwent valley (northern area)

Mam Tor Beds occupy the lower slopes of the Derwent valley between Marebottom Farm and Riding House, where, including strata now submerged beneath the reservoirs, they are at least 330 ft thick. A borehole immediately south of Howden Dam [SK 1693 9245] which commenced in strata approximately 80 ft below the top of the Mam Tor Beds, penetrated thin-bedded sandstones, siltstones and shales to at least 252 ft; these contained rare Dunbarella sp. and Anthracoceras or Dimorphoceras sp. in the lower part; beneath were strata of Edale Shales type, with a poor goniatite-bivalve fauna, extending to the bottom of the hole at 284 ft 6 in. Thin-bedded sandstones, siltstones and silty shales are well exposed along the lower reaches of Abbey Brook, Ouzelden Clough and Mill Brook. Rare indeterminate goniatites and fish debris are present in shaly beds 18–22 ft above the base of a small cliff [SK 17168974] on the western side of the outflow from Derwent Dam. In the west bank of the Derwent [SK 1720 8963], north of Ladybower Reservoir, Anthracoceras or Dimorphoceras sp., Homoceras sp., Reticuloceras sp. and acanthodian spines occur in shales 5 to 10.5 ft and 26 to 40 ft above the base of an alternating sequence of shale, siltstone and sandstone, 40 ft thick. Clayey, sandy and ferruginous nodules, the latter containing traces of oolitic structure, are present in this outcrop, and plant debris is fairly common. Stobbs (in Hind 1905, pp. 231–4) has recorded a fauna of bivalves, Orthoceras, goniatites and fish fragments from shales alternating with "grits" 30 to 60 ft below ground surface in the foundation trench of Derwent Dam. In 1959, lowering of the water level in Ladybower Reservoir due to drought revealed many outcrops of Mam Tor Beds, including typical basal shales with thin silty ironstone bands and rare thin ferruginous silty sandstones at the confluence of Mill Brook and the original course of the Derwent.

Edale, Mam Tor and Rushup Edge

On the northern slopes of the Edale valley the Mam Tor Beds vary from 225 ft to over 300 ft in thickness. The basal strata, consisting of shales and silty shales, locally ferruginous, with soft micaceous sandstones and thin bands and nodules of hard silty ironstone, can be seen overlying Edale Shales in Crowden Brook [SK 10218578] and Grinds Brook [SK 1208 8649], and in the River Noe [SK 1665 8586] north of the railway-bridge near Normans Farm. Alternating thin-bedded sandstones, siltstones and silty shales are exposed in many places in Crowden Brook, Grinds Brook, Oller Brook and Lady Booth Brook and in the Noe between Clough Farm and Normans Farm. Unidentifiable fragments of goniatites and pectinoids have been found in the lower part of the Mam Tor Beds in a landslip-scar [SK 1500 8604], 750 yd S.E. of Clough Farm (see p. 195) and in the banks of the Noe [SK 1667 8599] 0.5 mile S.E. of Edale End. G.D.G.

In the western part of the Edale valley the Mam Tor Beds maintain their usual lithological character, their thickness varying from 200 ft near Lee House to 350 ft near Chapel Gate [SK 105 840]. This southward thickening is partly due to the lateral passage of the lowest beds of the Shale Grit into Mam Tor Beds west of the Cowbum Tunnel entrance and partly due to an overall thickening. To the north-west of Lee House a sandstone up to 20 ft thick is present near the top.

Along the south side of the Edale valley the Mam Tor Beds thicken to about 400 ft near Barker Bank and Lose Hill. In Harden Clough a shale parting "about 50 feet above the base" (Hudson and Cotton 1945, p. 5) yielded Posidoniella sp., Dunbarella sp., Dimorphoceras sp., rare Reticuloceras sp. and Homoceras sp. I.P.S.

On Lose Hill, a short distance below the top of the Mam Tor Beds, a prominent feature indicates an abnormally thick bed of sandstone which either thins out or is laterally replaced by normal strata farther west, as seen in the Back Tor landslip-scar. G.D.G.

At the type locality of Mam Tor these beds are at least 450 ft thick. Some 400 ft of alternating sandstone and shale are exposed in the landslip-scar on the eastern side of the hill (see (Plate 16B)) and there are a further 50 ft of unexposed beds between the top of the scar and the summit, which must be just below the base of the Shale Grit. This section has been described in detail by Allen (1960, pp. 193–208).

Around Brockett Booth the Mam Tor Beds appear to contain little sandstone. Lateral passage of the uppermost beds into Shale Grit is described on p. 171.

To the west of Mam Tor the group can be traced below Rushup Edge as far as Rushup, though with some passage of the highest beds into the base of the Shale Grit. To the southwest of Rushup, however, the amount of sandstone within the group increases and the whole of the Mam Tor Beds passes into the basal beds of the Shale Grit before No. 10 Shaft [SK 0915 8129] of Coalpithole Mine is reached. I.P.S.

Hope Valley and Derwent valley (southern area)

In the Hope Valley, the Mam Tor Beds are over 300 ft thick. They form a marked hill at The Folly, about 0.33 mile S. of Hope. Several boreholes have been drilled here by Messrs. Earle to prove shale reserves; a typical hole (No. S5) [SK 1717 8295] (see also p. 201) passed through Mam Tor Beds of normal type to 82 ft 9 in; an 8 ft 3 in sandstone occurred at 36 ft 3 in and a 5 ft 9 in sandstone at the base. On the eastern side of the hill, the lower beds, here containing fewer and thinner sandstones than in the country to the north, are seen to overlie the Edale Shales in Messrs. Earle's shale quarries near Eccles House. The succession in the eastern pit [SK 1740 8286] is siltstone with rare thin soft micaceous sandstones and hard ferruginous sandstones 14 ft, on silty shale with siltstone bands 11 ft. In the western pit [SK 1736 8281] alternating thin beds of sandstone, soft silty and micaceous, with siltstone bands 5 ft, overlie silty shale and siltstone, with rare thin micaceous sandstones, 27 ft. Silty and sandy ferruginous nodules, plant fragments and thin carbonaceous streaks are also present. G.D.G., I.P.S.

The lower, mainly argillaceous Mam Tor Beds, are also exposed in the River Derwent, north-west of Bamford station. The upper part of the Mam Tor Beds in the Hope valley is thin-bedded sandstones, siltstones and silty shales similar to the succession farther north. Good exposures occur in the banks of the Noe, east of Hope and along the River Derwent for 500 yd downstream from its confluence with the Noe. They are strongly contorted and with slumped bedding in the bank of the Derwent [SK 1997 8415] north-west of Bamford.

Near Hathersage the Mam Tor Beds are 200 to 250 ft thick. The basal strata, silty shales with some thin silty ironstone bands and nodules, but with very few thin sandstones, are exposed in the stream [SK 2284 8108] 190 yd E. of Nether Hall. Thin-bedded sandstones and silty shales at higher horizons in the Mam Tor Beds are exposed intermittently in the stream from Brookfield Manor to Hathersage. G.D.G.

Between Brough and Shatton Moor the relations of the Mam Tor Beds to the Shale Grit are complex, with thicker sandstones making their appearance in the upper part of the group. One of these sandstones forms a marked scarp and dip-slope near Elmore Hill Farm. About 0.33 mile to the south several sandstones come in at a slightly higher horizon and thicken eastwards to join the lowest part of the Shale Grit. To the south of Brough it has not been found practicable to separate Mam Tor Beds, which here lose their identity.

Shale Grit

Glossop and Hayfield

To the north of Kinder Scout the Shale Grit forms a broad spread of moorland including Black Moor, Hurst Moor and Ramsley Moor. Between Leygatehead and Ramsley Moor the higher ground is formed by the upper part of the Shale Grit. Lower beds, however, are exposed (up to about 350 ft) in an inlier in Bray Clough [SK 056 917] and in a faulted inlier at Span Clough. Much of the area is obscured by peat, and stream sections show a normal development of massive sandstones with shale partings, the latter often silty and with thin sandstone bands.

A borehole at Messrs. Olive and Partington's works at Charlestown, Glossop [SK 0297 9331] (here called the Charlestown Borehole) showed that at least the upper part of the Shale Grit was absent at this locality, the base of the Kinderscout Grit being at 275 ft and the underlying beds, to the bottom of the hole at 851.5 ft, silty mudstones and siltstones with thin sandstone bands.

Between Kinder Reservoir and Oaken Clough the Shale Grit occupies a westward sloping tract, in many places approximating to a dip-slope. On the west the grit forms the sharp feature of Kinder Bank. Here several shale partings, each up to 30 ft in thickness, are present, though the intervening sandstones are very massive and have been quarried near Bowden Bridge and farther north [SK 0506 8802]. The latter section showed 100 ft of very coarse yellow-brown sandstone with pebbles up to half an inch and with thin leaves of silty mudstone in places. The available evidence suggests a thickness of 700 ft for the Shale Grit here.

South Head and Brown Knoll

Around the head of the Edale valley the Shale Grit forms steep slopes in which shale slacks and accompanying spring-lines run regularly and for considerable distances. The thickness of the Shale Grit is about 600 ft in the slopes north of Lee House and about 650 ft on, and west of, Horsehill Tor. In this area individual shale bands do not exceed 20 ft in thickness.

Between Horsehill Tor and South Head the Shale Grit forms a broad spread of upland, deeply dissected, and well exposed in Roych Clough and to a lesser degree in smaller cloughs near Upper Fold. An eastward extension of the outcrop forms Rushup Edge. Between Chinley and Chapel Milton, the Forge Works No. 2 Borehole [SK 0478 8202] probably passed through the Shale Grit (sandstones and shales with some thicker sandstone beds) between 480 and 730 ft. The higher beds in this borehole are difficult to correlate.

Bagshaw and Barmoor Clough

In the ground to the south of the Chapel en le Frith–Castleton road the Shale Grit dips westwards, and its broad outcrop approximates to a dip-slope. This area shows a marked contrast with that around Kinder Scout in the considerable irregularity of individual beds of sandstone and shale. There is an overall tendency for the group to thin to the south. Shale bands are mostly of normal thickness, though at Bagshaw shales about 100 ft thick are present towards the middle of the Shale Grit; these disappear northwards between Mag Low and Breck Edge by interdigitation with sandstone. To the south also the thick shale band is replaced by sandstone, though the horizon of its top and bottom may be traced for a further 0.75 mile southwards as minor shale partings. Near Coalpithole Mine No. 10 Shaft the lateral passage of the Mam Tor Beds into the base of the Shale Grit has already been noted (see p. 210). Between here and Barmoor Cough the lower part of the Shale Grit forms a well-marked escarpment. The southerly thinning is particularly evident near Barmoor Cough where several sandstones are observed to wedge out to the south-west, the intervening shale partings first joining and then disappearing in the same direction.

The sides of Barmoor Cough show well-bedded sandstones with shale partings which are overlain by coarse massive sandstones, at least 35 ft in thickness, in the approach cutting [SK 0722 7975] to the railway-tunnel north-east of Paradise. To the south of Barmoor Clough the Shale Grit thins rapidly and it disappears on the northern outskirts of Dove Holes. I.P.S.

Alport and Ashop valleys

In the upper Ashop and Alport valleys and on the adjacent moors the Shale Grit varies from 400 to over 600 ft thick near the summit of the Snake Pass. The following sequence, typical of the lower part of the Shale Grit, is exposed in the lower reaches of Ashop Clough [SK 1061 9069] and for a further 300 yd upstream:

feet

Sandstone with silty shale partings

14

Sandstone with thin siltstone bands

2

Siltstone with thin sandstone bands

2.75

Sandstone, massive

3.5

Siltstone with thin sandstone bands

8.75

Shale, silty, with thin sandstone bands

2.25

Shale, in part silty, with thin sandstone

bands in middle part

14.5

Shale, silty, with thin sandstone bands

6

Sandstone, massive

4

Shale, silty, and siltstone with abundant thin sandstone bands

14

Sandstone, flaggy, with many thin siltstone bands

7.75

Sandstone, massive

5

Beds of similar lithology are exposed in Swint Cough where some 413 ft of the lower and middle parts of the Shale Grit can be seen. The middle part of the Shale Grit is also well exposed in the Alport Castles landslip-scar [SK 142 915], where the following section was measured:

feet

Sandstone, medium- to coarse-grained, massive

22

Shale, silty with thin sandstone bands

5

Sandstone, massive

15

Sandstone, with thin silty shale and siltstone bands

39

Sandstone, massive

19

Shale, thin-bedded silty, alternating with siltstone and sandstone

5

Sandstone, massive

19

Sandstone, with thin silty shale and siltstone bands

18

Sandstone, massive

15

Shale, silty, and siltstone with thin sandstone bands

10

Shale, thin-bedded silty, alternating with sandstone

14

Shale, silty, and siltstone with thin sandstone bands

26

Sandstone with thin silty shale bands

8

Shale, silty, and siltstoe with thin sandstone bands

11

Sandstone

6

Similar strata outcrop in the Cowms Rocks landslip-scar [SK 124 905].

On the moors west of Lady Clough the thick massive sandstones of the middle part of the Shale Grit are succeeded by silty shales and siltstones up to 40 ft thick, exposed in the upper reaches of Upper Gate Clough, and overlain by a flaggy fine-grained sandstone with siltstone partings, about 30 ft thick [SK 0936 9175] and in small exposures for another 250 yd downstream.

A similar sequence, consisting of a thin sandstone overlying silty shale, forms outliers resting on the middle part of the Shale Grit on the moors west of Nether Reddale Cough, on the northern part of Hope Woodlands 1.5 miles N. of Alport Castles Farm and on Birchinlee Pasture. A fourth outlier is present on Rowlee Pasture and extends eastwards to Lockerbrook Heights, being exposed at the top of Bellhagg Tor [SK 1594 8951], where 39 ft of fine- to medium-grained well-bedded or flaggy sandstone, with thin siltstone bands in the upper part overlies 19 ft of silty shale, in turn resting on the middle part of the Shale Grit. Features on Rowlee Pasture 0.5 mile N. of Rowlee Farm indicate the presence of a second higher sandstone over a small area of moorland, but there are no outcrops.

In Fair Brook the upper part of the Shale Grit succession consists of 60 ft of medium-grained massive sandstone, becoming coarser towards the top, resting on 45 ft of silty shale with rare thin sandstone bands on massive fine-grained sandstone 26 ft, on silty shale 40 to 45 ft, overlying the middle part of the Shale Grit. Numerous small exposures of these upper beds can be found in the tributaries of Ashop Clough and Fair Brook. In Blackden Brook from [SK 1223 8842] to [SK 1198 8834] this succession, thinning eastwards, is estimated as follows:

feet

Sandstone, fine- to medium-grained, mainly well-bedded but in part massive

48

Shale, in part silty

12

Shale, with very thin sandstone bands

5

Sandstone, fine-grained

6

Shale, with thin sandstone bands

7

Shale

10

Features and small exposures in the streams suggest that a similar succession continues across Ashop Moor, but in Jaggers Clough from [SK 1453 8775] to [SK 1420 8774] the two sandstones are seen to have thickened out again, the succession being estimated:

feet

Sandstone, mainly massive medium- to fine-grained

58

Beds not exposed, believed to be shales about

25

Sandstone, mainly well-bedded medium-grained

45

Shale, in part silty, with rare thin sandstones

12

On Crook Hill features suggest that two sandstone bands in the upper shaly part of the Shale Grit are each approximately 30 ft thick, and old pits on these features contain fragments of fine-grained flaggy sandstone.

Upper part of Derwent valley

In the Derwent valley north of Crook Hill and on the adjacent moors, the Shale Grit varies from 350 ft to over 450 ft in thickness. Sandstones, predominantly medium-grained and well bedded, with subsidiary thin beds and partings of siltstone and silty shale, can be seen in many small outcrops in the lower Westend valley and adjacent tributaries north of Birchinlee Pasture, and in Ouzelden Clough and its tributaries. Near the top of Ouzelden Clough [SK 1510 9108], there is a continuous outcrop of 51 ft of medium- and coarse-grained massive sandstone, pebbly in places. Numerous exposures of sandstone are present in Abbey Brook. Farther south, the best exposures are in Mill Brook. Traced southwards the sandstones become better bedded, partly thin-bedded and flaggy, even the higher sandstones in the middle part of the Shale Grit losing their massive character, coarseness of grain and pebble content. Shaly partings and thin bands become thicker and increasingly numerous, and micaceous horizons in the sandstones become more pronounced. In a 40-ft outcrop of sandstone in a stream bank [SK 2055 8645] east-south-east of Ladybower House, only the top 20 ft is massive and coarse-grained, the remainder being flaggy, with thin siltstone bands.

Along the eastern flank of the upper Derwent valley the upper part of the Shale Grit consists of up to 150 ft of shales and siltstones with two thin sandstones, as on the moors to the west. The higher sandstone caps an outlier of these beds on Nether Hey. In Abbey Brook [SK 1948 9264] 25 ft out of an estimated total of 40 ft of silty shale are seen directly overlying the main sandstone sequence of the Shale Grit. The succeeding 6 ft of sandstone, fine-grained and flaggy, form a small waterfall 250 yd upstream [SK 1968 9256]. In a stream which joins Abbey Brook at this point, this sandstone is seen to be succeeded by silty shale 30 ft, this in turn being overlain by the higher sandstone, medium-grained well bedded, 40 ft. This higher sandstone forms a gorge at the confluence [SK 1979 9244] of Abbey Brook and a tributary stream. Farther south, in Far Deep Clough [SK 1873 9047], flaggy sandstone 12 ft, is seen overlying silty shale 8 ft, approximately 10 ft above the top of the main sandstone sequence of the Shale Grit. This sandstone maintains its thickness of 15 to 20 ft as far south as Riding House, beyond which it cannot be traced. The silty shales between the lower and higher sandstones are rarely exposed, but appear to decrease in thickness from nearly 40 ft on Abbey Bank to less than 15 ft at Riding House. The higher sandstone, 30 to 50 ft thick south of Abbey Brook, forms locally prominent features, such as Abbey Bank and Pike Low, with small outcrops in streams; old pits show mainly fine- to medium-grained well-bedded or flaggy sandstone. In the upper reaches of Far Deep Clough and Dovestone Clough nearly continuous outcrops indicate that it has thickened to about 70 ft; farther south it becomes increasingly flaggy and poorly exposed.

Edale valley

On the northern slopes of the Edale valley, the Shale Grit is 400 to 475 ft thick. Numerous outcrops of the main sandstone sequence occur in Crowden Brook, Grinds Brook, Oller Brook and Lady Booth Brook, consisting largely of medium-grained, well-bedded sandstones with subsidiary siltstone and silty shale bands and partings. The slopes between the streams are poorly exposed, and only one major shale horizon, at about the middle of the succession, can be traced continuously. The following section from Grinds Brook [SK 1182 8702] is typical of the lower part of the Shale Grit:

feet

Sandstone

12

Shale, in part silty

3

Sandstone

2

Not exposed

6

Sandstone

15

Shale, silty, with thin sandstone bands

7

Sandstone

6

Shale, silty

3

Sandstone, with thin silty shale bands

8

Alternating thin bands of silty shale and sandstone

3

Shale, in part silty

3

Sandstone

2

Somewhat higher strata are exposed in a quarry [SK 1517 8723] 0.75 mile N.W. of Edale End Farm:

feet

Sandstone, medium-grained massive

10

Sandstone, fine- and medium-grained, with thin siltstone bands

7

Sandstone, medium-grained massive

25

base and one in the middle of the succession, increase considerably in thicknes

The upper 25 ft of the main sandstone sequence are medium- to coarse-grained and massive in a series of exposures complicated by folding in the upper part of Grinds Brook [SK 1151 8718].

The shales succeeding the middle part of the Shale Grit are approximately 30 ft thick in Grindsbrook Clough, but thicken to over 50 ft in Oller Brook. Both the upper and lower sandstones which can be traced within the upper part of the Shale Grit, here totalling nearly 200 ft, are split by well-developed shale bands in Oller Brook, where they are both sporadically exposed. In Grindsbrook Clough they are largely obscured, but the upper sandstone appears to be at least 70 ft thick.

Hope valley

Approximately 230 ft of Shale Grit are present but poorly exposed on Lose Hill. In the Back Tor landslip-scar, 81 ft of the lower part of the Shale Grit can be seen resting on Mam Tor Beds. The exposed sequence consists of sandstones, thin-bedded and flaggy near the base, passing upwards into thicker units, with thin bands and partings of siltstones and silty shales decreasing in abundance up the succession.

On the steep slope under Hope Brink, west of Win Hill, four shale bands in the lower and middle parts of the Shale Grit are indicated by prominent spring lines. These horizons can be traced by means of localized features and individual springs along the south side of Win Hill, where the total thickness is over 400 ft. Exposures are few, small and confined to flaggy or well-bedded sandstones. Two distinct sandstone features can be traced in the unexposed shales forming the upper part of the Shale Grit around Win Hill. The higher bed appears to be approximately 50 ft thick, and outcrops as fine- to medium-grained sandstone 22 ft in an old quarry [SK 1796 8523] 0.5 mile W. of Win Hill summit.

Bamford and Hathersage

On the eastern slopes of the Derwent valley between Ladybower House and Hathersage the Shale Grit thins southwards from over 350 ft to slightly under 300 ft in thickness. The bands of argillaceous strata, particularly one near thes southwards from Brookfield Manor. The sandstones are, almost without exception, fine-grained, well-bedded or flaggy, with abundant thin micaceous bands and partings. Exposures in Dale Bottom, east of Hathersage indicate that the interbedded siltstones and silty shales account for at least 40 per cent of the thickness of the Shale Grit. The middle part of the Shale Grit is exposed [SK 2375 8174] along Dale Bottom:

feet

Siltstone

30

Sandstone, in part flaggy

9

Siltstone, with thin flaggy sandstone bands

16

Not exposed

6

Sandstone, in part flaggy

9

Siltstone, thin-bedded, alternating with sandstone

9

Sandstone

8

Sandstone with siltstone bands

6

Siltstone

7

Siltstone with thin sandstone bands

12

Sandstone with thin siltstone bands

14

Sandstone

2

Sandstone with thin siltstone bands

6

Siltstone with sandstone bands

17

The shales and siltstones of the upper part of the Shale Grit are not exposed south of Ladybower House, and there is no trace of the lower of the two sandstones known farther north and west. An outcrop [SK 2074 8664] of medium-grained fairly massive sandstone 4 ft, in the stream some 0.25 mile E.N.E. of Ladybower House, is part of the upper sandstone which forms a slight feature between this point and Greens House, 1.5 miles N. of Hathersage. It cannot be traced farther south, unless it equates with an isolated lenticular sandstone containing thin siltstone bands, which occurs within shaly strata at least 40 ft above the main sandstone sequence and is exposed at Kimber Court [SK 2384 8247] in the lane on the north-east side of the house. G.D.G.

Brough, Great Hucklow and Eyam

To the south of Brough the Shale Grit forms the complex features of Bradwell Edge, Durham Edge and Hucklow Edge. A sandstone, present beneath it in the Mam Tor Beds at Shatton (see also p. 211), when followed southwards is seen to join the base of the Shale Grit in a manner closely resembling that occurring near Sparrow Pit (p. 210). I.P.S.

In the high ground between Bamford and Abney the Shale Grit thins south-westward from over 350 ft to under 300 ft. It consists of an upper and lower group of sandstones containing thin interbedded shales and siltstones, separated by a thick succession of shales and siltstones with minor sandstones, and succeeded by a thin shaly sequence with a thin sandstone at the top. The lower part of the succession is flaggy sandstones with interbedded siltstones and silty shales in numerous small exposures along Abney Clough and Highlow Brook. The best outcrops of the upper sandstone group are in two minor streams between Banktop and Offerton Hall, and in Dunge Brook. The top of the highest sandstone is exposed in Dunge Brook [SK 2132 8037] as 13 ft of sandstone, in part flaggy. G.D.G.

Between Shatton and Abney the Shale Grit forms high ground, deeply dissected by Overdale Brook, which provides a typical section of the lower beds for some 500 yd below its source at Silver Well [SK 1872 8031]. Here the normal features of these beds, sandstones with numerous regular shale partings, are seen. On the western side of Bleak Knoll, at least 300 ft of Shale Grit are present. South of Abney the Shale Grit has fewer shale partings and these are limited to the lower part of the formation, much of the middle part consisting of a single bed of sandstone giving rise to the uniform dip-slope north-west of Abney, at Abney Grange and near Camphill Farm, with a narrow tongue extending westwards along the scarp to Bretton. A return to the normal development of sandstones with shale partings is apparent in the highest beds on Abney Low and Bretton Moor.

The full thickness of Shale Grit was passed through in Ladywash Shaft [SK 2189 7754], where 219 ft of interbedded 'gritstone' and 'shale' were recorded. To the south-east of this locality the grit continues to give rise to a marked escarpment though the shale partings disappear, giving a much more massive aspect to the subdivision than is usually the case. A typical section in a quarry [SK 2251 7651], near Riley House, showed coarse flaggy sandstone with many siltstone partings 18 ft, on massive coarse sandstone with sporadic siltstone partings 25 ft.

Between Eyam and the Derwent valley the Shale Grit forms a well-marked escarpment. At Calver the grit appears to fail, though it Seems to be present farther to the east at Curbar, from whence it can be traced, though thinning, in a southerly direction beyond the border of the district.

Beds between Shale Grit and Kinderscout Grit

Kinder Scout

These beds reach their maximum thickness of 350 to 400 ft on Black Ashop Moor, north of Kinder Scout. The beds are well exposed in the vicinity of Ashop Head and in the southern tributaries of Ashop Clough, as mudstones, silty mudstones and siltstones with thin sandstone bands. This lithology is typical.

Below Kinder Downfall the group is mainly obscured by landslip; its thickness here is about 300 ft. It thins southwards around the Kinder Scout plateau, being only 175 ft near Kinder Low, 150 ft at The Cloughs and 120 ft in Crowden Brook. I.P.S.

On Blackden and Ashop moors these beds are slightly over 250 ft thick and contain local lenticular sandstones in their upper part. The succession in the upper reaches of Blackden Brook [SK 1198 8834] to [SK 1171 8833] is:

feet

Shale, silty, and siltstone with thin sandstone bands

30

Sandstone, fine- to medium-grained, well bedded

28

Shale, silty, and siltstone with rare thin sandstone bands about

100

Sandstone, fine-grained

9

Shale, silty, with rare thin sandstone bands

78

There is a marked thinning eastwards, less than 200 ft of siltstone and silty shale with no distinct sandstones being present in Jaggers Gough, but between this valley and Lady Booth Brook an impersistent sandstone, estimated to be up to 40 ft thick, is developed about half-way up the sequence. About 220 ft of beds are present in the upper reaches of Grinds Brook, where nearly 100 ft of silty shales passing up into siltstones are seen resting on Shale Grit [SK 1098 8729]; there are continuous sections upstream for 200 yd. A number of sandstone bands, generally less than 1 ft thick, are of two main types: either soft, lenticular, micaceous and flaggy, or hard, strongly cemented and nodular. Some 40 ft of siltstones with thin sandstone bands are seen immediately below the Lower Kinderscout Grit farther upstream [SK 1069 8729]. A sandstone feature is present around the eastern and southern slopes of Grindslow Knoll. G.D.G.

Western outcrops

To the east of Chunal some 350 ft of shale, siltstone and thin sandstone are present at this horizon. A section in the upper part of Whitethorn Clough [SK 0466 9085] showed silty mudstone with thin sandstones 14 ft, soft shale, 'sulphurous' at base, silty and 'blocky' above 22 ft, on silty shale with thin flaggy sandstones and siltstones 10.5 ft. In this vicinity lenticular sandstones are present near both the base and top of the group.

The Charlestown Borehole (see also pp. 363–4) passed through the Kinderscout Grit into shale, part of which must belong to the present beds, but with the failure of the Shale Grit the subdivision loses its identity and these shales are best considered as a whole.

To the south of Hollingworth Clough a rapid thinning of the beds between the Kinderscout Grit and Shale Grit takes place: from at least 300 ft in Hollingworth Clough to some 50 ft on Middle Moor. In the Kinder valley only some 30 ft of shale are present, but between there and the slopes [SK 052 861] to the west of Coldwell Clough, lateral passage of the uppermost part of the Shale Grit into shale results in a substantial thickening of the subdivision. From the last locality the beds continue southwards, though displaced by faults, as far as Upper Fold. South of this point they can be followed as a shallow depression, often drift-filled, to Chapel Milton. South of Chapel en le Frith the outcrop expands greatly owing partly to a flattening of the dip, partly to the inclusion within the subdivision of shale which is the lateral equivalent of the lower part of the Kinderscout Grit (see p. 219), and partly to thickening; in all some 350 ft of shale are present here. At Martinside and near Cow Low, lateral passage of the upper part of these beds into Kinderscout Grit takes place, and the group thins in consequence. Near Dove Holes it loses its identity with the southerly disappearance of the Shale Grit. I.P.S.

Eastern outcrops

The succession on Win Hill, estimated to be just over 150 ft thick, is not exposed, but old pits in a narrow feature around the upper slopes contain fragments of fine-grained flaggy sandstone. On Crook Hill a vestigial feature on the north-eastern slope suggests the local development of a similar sandstone.

East of the Derwent valley and north of Ladybower House, the beds between the Shale Grit and Kinderscout Grit vary from 100 ft to 200 ft thick, for although in general the strata thin out to the south, the succession is expanded locally owing to wedging out of successive units of the lower part of the Lower Kinderscout Grit with consequent addition of the equivalent and intervening strata to the sequence below. Between Abbey Bank and Pike Low two thin impersistent sandstones form features in the otherwise concave slopes of these beds and old pits along the outcrops contain loose fragments of fine-grained flaggy sandstone. A similar impersistent sandstone feature is present on the slopes east of Riding House. Exposures of the argillaceous strata are rare. Sporadic outcrops of silty shales, siltstones and very thin sandstones, the latter either hard and nodular or soft and micaceous, occur in a stream which joins the upper part of Abbey Brook near the shooting cabin, and a thin ripple-marked sandstone occurs in the stream [SK 1968 9198] near the top of these beds. In Dovestone Clough [SK 1921 8980] 8 ft of silty shale, with very thin hard sandstone bands, crop out a few feet above the top of the Shale Grit.

Under Bamford Edge there appear to be about 200 ft of beds between the Shale Grit and Kinderscout Grit. An impersistent coarse massive sandstone, at least 20 ft thick, is present in the upper part of these beds, forming crags on the steep slopes of Priddock Wood [SK 2065 8642]. Outcrops of siltstone and silty shale with rare thin sandstone bands occur in a number of small exposures in the upper reaches of the stream east of Bamford Filters, at approximately 400 yd S.W. of Bole Hill. Siltstones with thin sandstone bands, 11 ft thick, crop out [SK 2373 8348] east of North Lees. A number of small outcrops of the strata underlying the Kinderscout Grit, mainly siltstone and silty shale, laminated and micaceous, with abundant thin sandy bands and partings, are present in a stream [SK 238 835] east-north-east of North Lees. Outcrops of micaceous siltstone and silty shale with very thin hard flaggy sandstone bands occur in Dale Bottom between 200 yd and 470 yd W. of Mitchell Field.

The argillaceous beds between the highest sandstone on Offerton Moor, which is considered to be Kinderscout Grit, and the Shale Grit below, decrease in thickness southward across the moor from 150 ft to less than 100 ft. In Dunge Brook [SK 2132 8037] siltstones with thin flaggy sandstones 9 ft, overlie the top of the Shale Grit. Some 85 yd farther upstream [SK 2125 8039], and a few feet below the base of the Kinderscout Grit, 6 ft of silty shale are exposed. G.D.G.

On the western side of Shatton Moor from 100 to 120 ft of shale are present at this horizon. The top is irregular owing to lateral passage into the lowest part of the Kinderscout Grit.

Ladywash Shaft (see p. 372), commencing about 20 ft below the base of the Kinderscout Grit, passed through made ground to 29 ft and continued in shale to 93 ft before reaching sandstones referred to the Shale Grit. The beds thin eastwards from this locality and, with the disappearance of the Shale Grit at Calver Sough, cannot be recognized beyond this point.

Kinderscout Grit

Kinder Scout

At the type locality the Lower Kinderscout Grit, about 300 ft thick, forms an elevated plateau; the Upper Kinderscout Grit is absent. Much of the outcrop is obscured by peat. The grit is typically a very massive coarse-grained feldspathic sandstone, cross-bedded and pebbly in places, characters well shown at Kinder Downfall [SK 0815 8883] (see (Plate 18A)) where 265 ft of it are exposed. The section below Crowden Tower [SK 0959 8706], shows 240 ft of the same beds overlain by a shale band some 20 ft thick, and the latter by 40 ft of coarse sandstone forming the top of the escarpment. Elsewhere shale partings occur infrequently near the base of the grit on the northern edge of the plateau [SK 091 899] and on its westward extension. Shale bands, including the one seen at Crowden Tower, are also present along the south-western edges of the plateau as at Edale Head. I.P.S.

Under Seal Edge the lower and upper leaves of the Lower Kinderscout Grit appear to be united, but in the upper reaches of Blackden Brook [SK 1170 8834], the lower leaf is present as coarse-grained sandstone 34 ft thick, succeeded by 33 ft of siltstone with thin sandstone bands. The same leaf forms a rather ill-defined feature under Blackden Edge, becoming more distinct eastwards, where [SK 1397 8855], 0.33 mile W.N.W. of Crookstone Knoll, 17 ft of coarse-grained pebbly sandstone are exposed. Ripple-marks are seen in siltstones and thin sandstone bands in a stream running down Blackden Edge [SK 1290 8819], between the lower and upper leaves of the Lower Kinderscout Grit. The lower leaf and overlying beds are seen in Jaggers Clough [SK 1410 8774]:

feet

Siltstone and silty shale

11

Sandstone, massive

1

Sandstone, flaggy

1

Siltstone

3

Sandstone, with thin siltstone bands and partings

11

The lower leaf is apparently not present between the upper reaches of Lady Booth Clough and Golden Cough, but it can be seen at the base of Nether Tor, where 12 ft of sandstone are separated from the upper leaf by 17 ft of siltstone with thin sandstone bands. In a stream [SK 1100 8756] west of Upper Tor, this succession is reduced to 6 ft of sandstone overlying 12 ft of siltstone, but it thickens in the upper reaches of Grindsbrook Clough, where in a crag [SK 1075 8735], 17 ft of sandstone are exposed. The succeeding argillaceous beds are 15 to 25 ft thick in this locality, but are nowhere exposed. The lower leaf forms a local feature south-west of Grind-slow Knoll, with small exposures of coarse-grained pebbly sandstone, mainly massive, but this feature cannot be traced northeastwards around the head of Crowden Brook.

The upper leaf of the Lower Kinderscout Grit is about 80 ft at the eastern end of the Kinder Scout plateau, thickening westwards to about 150 ft south of Seal Edge. Abundant crags and residual blocks, mainly of massive coarse-grained pebbly sandstone, are present on Seal Edge. A continuous exposure of 72 ft of sandstone occurs along Blackden Brook [SK 1166 8836] westwards for 100 yd. It is mainly massive and coarse-grained, and locally pebbly, but some medium-grained well-bedded and even flaggy varieties can be seen. False-bedding is present in the craggy outcrops 100 yd south of this point.

In exposures along Jaggers Gough, westwards for 190 yd from a point [SK 1406 8778] 0.75 mile N. of Rowland Cote, 53 ft of mainly massive coarse-grained and pebbly sandstones are succeeded by 17 ft of medium to coarse-grained sandstone, mainly well-bedded or flaggy.

In addition to crags and residual blocks on top of the plateau, the southern edge of Kinder Scout north of the Edale valley shows a number of cliff-like outcrops in which the massive coarse-grained pebbly nature of the sandstones can be seen. Up to 42 ft of sandstone crops out at the western end of Ringing Roger, up to 65 ft on Nether Tor, and up to 75 ft on Upper Tor. Where Grinds Brook cuts down through the edge of the plateau [SK 1066 8744] and for 100 yd upstream, the succession is:

feet

Sandstone, well-bedded medium- to coarse-grained

35

Sandstone, false-bedded coarse-grained pebbly

45

Sandstone, flaggy fine- to medium-grained, with micaceous silty partings

4

Sandstone, false-bedded coarse-grained pebbly

30

Numerous crags and residual blocks of sandstone are present on Grindslow Knoll. Towards the centre of the plateau, streams have cut through the peat to expose abundant loose blocks and small exposures of sandstone; these are mainly massive or well-bedded, medium- to coarse-grained, but include some thin-bedded flaggy sandstones. G.D.G.

Glossop to Chapel en le Frith

In this area the Kinderscout Grit contains a thick bed of shale with the Butterly Marine Band, separating the Lower Kinderscout Grit from the thinner Upper Kinderscout Grit. The three separate components are described separately below. In all but the southern part of this area (see below) the Upper Kinderscout Grit is closely overlain by the Reticuloceras gracile Marine Band. Both sandstone leaves give rise to marked scarp and dip-slope features, although where the shale underlying the Lower Kinderscout Grit thins, as on Kinder Bank, Hayfield, the lower scarp disappears and a composite feature of Kinderscout Grit and uppermost Shale Grit results.

The Lower Kinderscout Grit, some 250 ft thick, reaches its thickest development in the Hayfield area. A typical section is provided by the old quarries [SK 0432 8658] south of the Sportsman's Inn, where some 160 ft of yellow-brown massive coarse-grained sandstone show large-scale cross-bedding, with some channelling of individual beds. Farther north, Hollingworth Clough provides a good section of massive cross-bedded coarse and frequently pebbly sandstone. From this locality the grit thins northwards, being some 150 ft thick east of Chunal. The Charlestown Borehole (see pp. 363–4) proved only 74.5 ft of Lower Kinderscout Grit, with the base at 275 ft; the upper 12 ft were coarse-grained but contained argillaceous partings; they were underlain by a 2.5-ft bed of silty mudstone resting on 1 ft of silty seatearth with rootlets at 216 ft. The underlying sandstone was coarse and massive with pebbly bands though the lowest 8.5 ft formed a passage to the underlying shale.

To the south of Hayfield, also, the Lower Kinderscout Grit varies greatly. Between the River Kinder and Mount Famine, its development continues as in the north. To the south and south-east, however, the grit emerges southwards from a much-faulted area as two distinct leaves. The uppermost of these again splits southwards into two parts, both of which die out between Andrews Farm and a point 700 yd south of it. The lower leaf maintains its character southwards as a coarse massive pebbly rock and gives rise to the strong scarp of South Head. It is exposed in the following section [SK 0566 8212] in the railway-cutting south-east of New Smithy [top of section at [SK 0534 8232]:

feet

Sandstone, yellow-brown well-bedded, with a few flaggy partings

12

Sandstone, massive coarse feldspathic

40

Shale, silty, with thin sandstone bands

9

Sandstone, yellow-brown well-bedded medium-grained

6

Sandstone, yellow-brown massive

coarse

20

The total thickness here is about 110 ft.

The last exposure of any importance of the depleted Lower Kinderscout Grit is in the railway-cutting [SK 0557 8164) south of Chapel Milton, where sandy shale overlies 27 ft of massive feldspathic sandstone. Farther south the small feature at Chapel en le Frith suggests that the whole bed degenerates and passes into shale about a quarter of a mile south-west of the town.

A complete section of the shales with the Butterly Marine Band, 87 ft 3 in thick, is provided by the Charlestown Borehole:

Thickness

Depth

feet

inches

feet

inches

Base of Upper Kinderscout Grit

113

3

Mudstone, silty, and siltstone with sandstone bands

25

9

139

0

Sandstone, argillaceous, with partings of silty mudstone and siltstone in lower part

26

5

165

5

Mudstone, pale grey with thin bands and occasional lenses and nodules of ironstone

4

7

170

0

Butterly Marine Band

Mudstone, lithology as above; Sanguinolites sp. and bivalve fragment indet. at 170 ft to 170 ft 6 in; palaeoniscid scale 182 ft; coiled shell indet. 184 ft; Lingula mytdkides, Retispira ? [juv.], Rhabdoderma sp. [scales] at 185 ft 3 in; L. mytilloides, Polidevcia aff. attenuata (Fleming), Sanguinolites sp. [juv.] 186 ft to 187 ft 9 in cf. Cochlichnus kochi, Planolites?, cf. Cypridina sp. 188 ft 4 in to 188 ft 6 in; L. mytilloides, Sanguinolites ovalis 189 ft to 190 ft 2 in; L. mytilloides, turreted gastropod indet., Sanguinolites ovalis, Reticuloceras sp. nov., mollusc spat 191 ft 6 in to 192 ft 9 in; L. mytilloides, Orbiculoidea nitida, Retispira undata, Aviculopecten aff. dorlodoti, Edmondia sp., Polidevcia aff. attenuata, Sanguinolites ovalis, S. cf. tricostatus, Schizodus antiquus Hind, Ephippioceras? 193 ft 3 in to 197 ft 3 in

27

3

197

3

Mudstone, dark platy micaceous, with some irregular pyrite

1

11.5

199

2.5

Coal

3.5

199

6

Seatearth, banded silty with rootlets

1

0

200

6

This is a much fuller development of the Butterly Marine Band than anywhere at outcrop in the district. Non-marine interdigitations are present at 182 ft and between 188 ft 4 in and 188 ft 6 in. Other aspects of the fauna have already been discussed on p. 177.

A sectionMeasured by Mr. C. G. Godwin. on Chunal Moor [SK 0376 9151] is:

feet

Base of Upper Kinderscout Grit

Not exposed

about 10

Mudstone, sandy

5

Mudstone, grey silty, darker below

14

Mudstone, dark grey; Reticuloceras sp. nov.; fish debris

1

Not exposed

about 5

Lower Kinderscout Grit

Another section [SK 0361 9054] in a stream east-north-east of the Grouse Inn showed a greater thickness of shale:

feet

Sandstone, coarse, thin-bedded in lower part

10

Mudstone, silty

20

Sandstone, thin-bedded

about 3

Mudstone, sandy

4.5

Mudstone, very silty at top, less so below

20.5

Mudstone, dark shaly with Lingula mytilloides, Aviculopecten aff. dorlodoti, Sanguinolites ovalis, Reticuloceras sp., mollusc spat

5

Mudstone, dark silty; plant debris

0.5

Mudstone, grey with rootlets and lenses of ganister-like sandstone

2.75

Lower Kinderscout Grit

This section, although farther away from the Charlestown Borehole than that quoted above, shows a closer similarity to it. This is due to the northward thickening of the 3-ft sandstone present within the shale near the Grouse Inn and its junction with the main bed of the Upper Kinderscout Grit. Rapid variations in the thickness of the shale to the south are probably due to the same cause.

At Little Hayfield the beds between Upper and Lower Kinderscout grits, poorly exposed, are about 60 ft in thickness.

The southernmost exposure [SK 0458 8603] showing the Butterly Marine Band is 0.25 mile N. of The HeysMeasured by Mr. C. G. Godwin.:

feet

Upper Kinderscout Grit

Not exposed

30

Mudstone, dark silty, becoming less silty below

9

Mudstone, dark fossiliferous, especially at 3 in from top and at base; Reticuloceras sp. nov., mollusc spat

21

Mudstone, dark; goniatite fragment and rare plant debris

11

Mudstone, dark silty and sandy, part tending towards seatearth,

about 1

Lower Kinderscout Grit

To the south of Mount Famine the lateral passage of part of the Lower Kinderscout Grit into shale results in a considerable thickening of the shales between the Upper and Lower Kinderscout Grit, which here reach 350 ft. In the region of this passage the horizon of the coal of the Charlestown Borehole is perhaps represented [SK 0529 8435] north-north-west of Andrews Farm by 2.5 ft of soft black micaceous silty mudstone resting on black micaceous siltstone. Lower beds in these shales are exposed in the stream, from a point 200 yd E. of Andrews Farm, downstream for a third of a mile as silty mudstones and siltstones with thin sandstone bands. To the south, the shale group, though thinning, can be traced through Chapel Milton and Chapel en le Frith. Beyond the latter place, with the disappearance of the Lower Kinderscout Grit, it cannot be recognized, and has been included with the beds between Kinderscout Grit and Shale Grit.

In the Charlestown Borehole the Upper Kinderscout Grit is represented by at least 62 ft 7 in of beds, with the base at 113 ft 3 in; the lithology is mainly fine- to medium-grained sandstone, micaceous and flaggy in places and with carbonaceous partings. Coring commenced 10 in below the top of the sandstone, so details of the overlying beds are lacking.

The Upper Kinderscout Grit, some 90 ft thick, forms a well-marked dip-slope between Chunal and The Intakes. Workings [SK 0352 9128] 0.25 mile S. of Chunal show a typical section: coarse feldspathic sandstone with fine-grained flaggy bands 13 ft. The beds separating the grit from the overlying Reticuloceras gracile Marine Band are represented by a thickness of 2 ft of unexposed beds in the stream north-west of the Grouse Inn (see p. 226).

Between The Intakes and Brookhouses the outcrop of the Upper Kinderscout Grit is much broken by faulting, but farther south it resumes its regular character with well-marked dip-slopes. Like the Lower Kinderscout Grit it reaches its maximum development in the Hayfield area, where it is from 100 to 150 ft thick. The best sections are in several quarries south of Chinley Head; a typical section [SK 0503 8429] near the Lamb Inn showed 28 ft of yellow massive coarse felds pathic sandstone, with bands of small pebbles up to 0.25-in diameter throughout, scattered shale pellets and a shale lens (2 ft by 8 ft) near base, on 0 to 14 ft of massive sandstone as above, but with some finer bands and full of plant debris, on 18 ft of massive sandstone, as above. Southwards the thickness of the leaf is maintained, being about 120 ft in and around the railway-cutting at New Smithy west end: [SK 0474 8267].

The borehole at Whitehall Works [SK 0355 8202] proved the base of the Reticuloceras gracile Marine Band at 467.5 ft. Below were 40.5 ft of silty micaceous mudstones with thin siltstone bands, proved to 508 ft. No Kinderscout Grit was found and it is considered that the silty beds are its lateral equivalent rather than an expansion of the few feet of beds which normally lie between the top of the grit and the R. gracile Band.

Between Chapel Milton and Lower Crossings the Upper Kinderscout Grit gives rise to a fairly well-defined escarpment. South of Lower Crossings the outcrop passes beneath drift.

Martinside to Buxton

In this area only one main bed of Kinderscout Grit is present, though this is subject to minor variation. As noted above in the Whitehall Works Borehole. the upper part of the Kinderscout Grit locally passes laterally into more argillaceous and silty beds, especially around Martinside. Here the exposure of the R. gracile Marine Band north-east of Ridge Hall (see p. 229) lies about 100 ft above the Kinderscout Grit, the intervening beds being mainly siltstones and silty mudstones. The Kinderscout Grit at Martinside (the Upper Kinderscout Grit of the country to the north) splits southwards into three principal leaves and it is the middle one of these which persists, the other two dying out rapidly. South-east of Cowlow the grit is somewhat irregular, being split into a number of variable components. The best section here is that in a quarry [SK 0693 7871] showing 32 ft of yellow-brown massive coarse-grained sandstone in beds up to 6 ft thick, with flaggy partings. At Cowlow (see also p. 229) there is room for some 90 ft of mainly argillaceous beds between the base of the R. gracile Band and the top of the Kinderscout Grit.

Between Dove Holes and the southern boundary of the district the Kinderscout Grit consists of a more regular upper portion from 60 to 80 ft in thickness, underlain by one or more thin lower leaves; the overall thickness not exceeding 120 ft. Sections are scarce, though a quarry [SK 0698 7702] southwest of Dove Holes showed about 25 ft of sandstone, mostly rather coarse-grained. At Blackedge Reservoir there is room for about 100 ft of argillaceous beds between the top of the Kinderscout Grit [SK 0680 7650] and the R. bilingue Band; this suggests a southerly thinning from Cowlow of the beds between the R. gracile Band and Kinderscout Grit to perhaps 70 ft. This is further borne out by the section in Hogshaw Brook, in the Buxton (111) district, where the R. bilingue early form Marine Band [SK 0598 7422] lies about 40 ft above the Kinderscout Grit suggesting that the R. gracile Band (which is not exposed) is at or near to its normal position close above the Kinderscout Grit. Beyond the southern edge of the district, the Kinderscout Grit thins south-west of Hogshaw Brook and dies out [SK 0575 7385] near the Palace Hotel, Buxton.

Todd Brook Anticline

Towards the northern end of this structure the Kinderscout Grit, some 180 ft thick and free from shale partings, passes round the axis, forming a sharp feature. Exposures are good only near Lumbhole Mill; a typical one [SJ 9872 8039] showed brown massive sandstone with micaceous partings 12 ft, siltstone and silty mudstone with sandstone bands 7 ft, on flaggy sandstone 1 ft 2 in. The outcrop of the Kinderscout Grit is repeated by faulting 0.25 mile S.W. of Bailey's Farm.

Between Kettleshulme and Hollowcowhey there is a fairly regular arrangement of the Kinderscout Grit. The calculated section near Dunge Farm is typical: upper leaf 320 ft, shale 55 ft, lower leaf 70 ft. South of Hollowcowhey the grit has irregular shale partings and there is some tendency for the lower leaves to die out. The grit gives rise to a sharp feature at Andrews Edge running south from a point [SJ 9857 7543] near Redmoor Farm. A small exposure east of Andrews Edge [SJ 9853 7514] shows flaggy sandstones with shale and siltstone partings. The outcrop passes over the axis of the Todd Brook Anticline near the southern boundary of the district and continues northwards to Nab End; from thence to Kettleshulme it is faulted out. I.P.S.

East of the Derwent

The lower leaf of the Lower Kinderscout Grit is about 150 ft thick north of Howden Dean, where it forms the main escarpment of Howden Edge above Howden Moors. There are few exposures, but loose blocks of coarse pebbly sandstone are widespread. East of this edge a series of ill-drained slacks suggests the presence of minor shale bands. Around the head of Abbey Brook the lower leaf consists of a lower bed of medium- to fine-grained well bedded and flaggy sandstone with subsidiary argillaceous bands, and an upper bed of mainly massive coarse sandstone, which rests, with apparent slight discordance in places, on up to 50 ft of siltstones and silty shales. The complete succession of the lower leaf in Bent's Clough [SK 2000 9244], is:

feet

Sandstone, massive coarse-grained

55

Shale, silty with siltstone bands

15

Sandstone, massive medium- to fine-grained

12

Shale, silty

15

Sandstone, flaggy medium- to fine-grained

30

Shale, silty, and siltstone

10

Not exposed

6

Sandstone, flaggy fine-grained

12

The lower bed is not more than 30 ft thick on the moors south of Howden Dean, where loose fragments and small outcrops in old quarries are mainly of fine- to medium-grained sandstone, and no further trace of this bed is present south of Dovestone Clough. The upper bed forms a prominent feature on Lost Lad Hillend [SK 191 914], where there are abundant loose blocks of massive medium- to coarse-grained sandstone. This feature can be traced southwards, decreasing in magnitude across the Gusset and Dove-stone Clough, where fine-grained flaggy sandstone with thin siltstone bands is exposed, until it finally disappears under Whinstone Lee Tor.

The strata between the lower and upper leaves of the Lower Kinderscout Grit are about 120 ft thick north of Low Tor. Numerous small exposures of siltstone and silty shale with thin sandstone bands occur in the highest reaches of Abbey Brook 2.25 miles E.N.E. of Marebottom Farm. No exposures are present on the slopes west of Low Tor, Howshaw Tor and Back Tor, but in the upper reaches of Dovestone Clough, where the total sequence is approximately 80 ft, there are small exposures of silty shale with thin siltstone and sandstone bands. No outcrops occur under Derwent Edge farther south, where with the disappearance of the lower leaf, these strata overlie and become indistinguishable from the beds between the Shale Grit and Kinderscout Grit.

The upper leaf of the Lower Kinderscout Grit is not much more than 80 ft thick N.N.E. of Low Tor, where it forms a small but well-defined feature with scattered blocks of massive coarse-grained pebbly sandstone. Between Howshaw and Whinstone Lee Tors, on Derwent Edge, it has increased to 120 to 180 ft in thickness and forms the main escarpment overlooking the Derwent valley. The numerous crags on Derwent Edge consist of predominantly massive coarse-grained pebbly sandstone. Other features present are small-and large-scale false-bedding, generally dipping to the south-west; less commonly load and flute marks on the under surfaces of sandstones in contact with thin shaly bands or partings; shale conglomerates and large soft sub-spherical brown concretions which weather into hollows. The most common topographical features are large cliff-like faces of considerable lateral extent forming the highest scarp slopes such as those under Back Tor and Dovestone Tor and residual blocks and towers situated on the tops of the scarp, such as the Salt Cellar and the Wheel Stones. The existence of very large-scale false-bedding planes dipping south-westwards is evident along Derwent Edge, and the resulting features give a misleading impression of successive beds dipping southwards along the scarp, each being separated from the next by a well-marked 'slack'. These 'slacks', although suggestive of the presence of shales, are considered more likely to be the outcrops of soft, usually coarse-grained beds at the base of the false-bedding units. Approximately 80 ft of mainly massive coarse-grained pebbly sandstone is exposed under Dovestone Tor.

On Ladybower Tor sandstones, mainly massive coarse-grained and pebbly, but with subsidiary thin-bedded medium-grained bands, about 75 ft thick, are exposed in the landslip-scar. Continuous exposures of similar lithology occur along the roadside for 700 yd S.W. of Cutthroat Bridge. Well developed south-westerly dipping false-bedding is visible in a large quarry [SK 2083 8684] 0.33 mile N.E. of Ladybower House.

On Bamford Edge the Lower Kinderscout Grit is approximately 140 ft thick, with craggy outcrops up to 40 ft high of massive coarse-grained pebbly sandstone, in which south-westerly dipping false-bedding is fairly common. At the southern end of Bamford Edge, 0.75 mile N.N.E. of Bamford church, large-scale false-bedding gives rise to 'slacks' as described on Derwent Edge. In a quarry [SK 2153 8432] 0.75 mile N.E. of Bamford church, 40 ft of sandstone, mainly massive and coarse-grained, but with some thin-bedded bands, show south-westerly dipping false-bedding.

Between Bole Hill and Scraperlow, 0.75 mile E. of Hathersage, the Lower and Upper Kinderscout grits appear to be united, the total thickness of both grits decreasing southwards from 140 to 70 ft at Mitchell Field. Massive medium- to coarse-grained sandstone, locally pebbly, is well exposed in the stream east of Sheepwash Bank and on Carhead Rocks. South of Scraperlow the feature of the Lower Kinderscout Grit can be distinguished 200 yd E. of Kettle House, suggesting a thickness of about 45 ft. Sandstone, fine- to medium-grained, in part fissile, flaggy and micaceous, with siltstone partings, crops out in quarries [SK 2400 8121] 0.25 mile W.S.W. of Scraperlow. Farther south medium- to coarse-grained sandstone is visible in a roadside exposure [SK 2404 8067] 200 yd S. of Hathersage Booths.

The beds between the Lower and Upper Kinderscout grits are nearly 70 ft thick north-west of Honing Dale, where they form an ill-drained 'slack' with no exposures. In the stream [SK 2145 9215] 0.25 mile N. of Foulstone Delph, the following beds rest on the ganister-like top of the Lower Kinderscout Grit, which contains rare Stigmaria casts:

feet

inches

Siltstone, with thin flaggy sandstone

bands

7

0

Siltstone and silty shale

11

0

Shale, dark grey near base, becoming silty near top

12

0

Shale, dark grey; Palaeoneilo sp., palaeoniscid scales and Reticuloceras sp. nov.

11

Shale, grey

5

0

The Butterly Marine Band is here less fully developed than in the north-western exposures, showing only the goniatite-phase at the base.

The feature formed by a 7-ft impersistent sandstone occurs immediately above this exposure, and in a number of outcrops 220 to 480 yd farther downstream, the overlying silty shales and siltstones, with thin sandstone bands, are visible. In a stream bank [SK 2136 9102], just north-west of Foulstone Delph, 30 ft of silty shale and siltstone are seen underlying the Upper Kinderscout Grit, and the same strata are exposed higher up this stream, where the total sequence is estimated to be 40 to 45 ft thick. On the moors farther south, only the vaguest trace of a 'slack' is present, but in the middle reaches of Highshaw Clough, these beds appear to have maintained a thickness of about 45 ft, and numerous exposures of silty shales and siltstones with thin sandstone bands are present. Silty shales, highly contorted owing to the proximity of the Moscar Fault, are seen in outcrops in the stream 0.25 to 0.33 mile E.N.E. of Cutthroat Bridge.

The beds between the Lower and Upper Kinderscout Grit form a wide bench under Hordron Edge, where they are estimated to be nearly 75 ft thick. There are no exposures, but two low features suggest the development of thin sandstones. On Bamford Moor the position of these beds is uncertain. They are not exposed, but three narrow slacks suggest the existence of shaly bands separated by two substantial sandstones which, as the slacks merge southwards, evidently die out. It would appear that the two grits join at Bole Hill, as no evidence for the existence of the intervening beds can be found between Bole Hill and Scraperlow. Features south of Scraperlow suggest the separation of the two grits by intervening shaly beds, but these, estimated to be 20 to 30 ft thick, are not exposed.

The Upper Kinderscout Grit is 60 to 90 ft thick between Holling Dale and Bamford Moor. It forms wide gentle dip-slopes on Holling Dale and Foulstone Moor, but is poorly exposed both on the moors and on the distinct but shallow west-facing scarps. The lower reaches of streams draining Brogging Moss show sandstone varying from flaggy fine-grained to massive coarse-grained and locally pebbly, and with fairly common false-bedding. The highest beds are exposed in many outcrops in Strines Dike and in the stream between Holling Dale Plantation and Bole Edge Plantation, here mainly medium-to fine-grained well-bedded, locally ganister-like, and containing rare casts of Stigmaria. Farther south an exposure in Rising Clough [SK 2189 8849] shows 10 ft of sandstone, massive coarse-grained and slightly pebbly, but with some flaggy beds and southerly dipping false-bedding, these beds being 10 to 20 ft below the top of the Upper Kinderscout Grit. A large slab of ripple-marked sandstone is present in Rising Clough 15 to 20 yd downstream from the above outcrop. In a borehole [SK 2349 9179] north-north-east of Hallfield, the Upper Kinderscout Grit was recorded as 'grey rock' between 150 ft and the base of the borehole at 191 ft 6 in.

The Upper Kinderscout Grit is mainly massive or well-bedded medium- to coarse-grained sandstone on Hordron Edge, where abundant residual blocks and a number of small outcrops occur. On Bamford Edge, only a very subdued feature is present, a typical exposure [SK 2130 8534] being coarse-grained pebbly sandstone 8 ft.

The beds between the Kinderseout Grit and R. gracile Marine Band consist of up to 13 ft of strata. A thin coal and seatearth are, sometimes present at the base and these are overlain by mudstone and micaceous siltstone with thin sandstone. In a stream bank [SK 2330 9289] nearly a mile north of Hallfield, shaly coal, with carbonaceous shale, 0 to 5 in thick, overlies grey micaceous mudstone 12 ft. The succession in another stream bank [SK 2259 9200] west-north-west of Hallfield and for 100 yd downstream is:

feet

inches

Shale, dark grey, with plant fragments

1

0

Sandstone

2

Mudstone, dark grey carbonaceous

1

Mudstone, dark grey, with rootlets

near top

4

0

Lateral variation of these beds is illustrated in an exposure [SK 2214 9100] mile 0.5 E. of Foulstone Delph:

feet

inches

Coal, passing laterally into black carbonaceous shale

2

Mudstone, dark grey

1 ft to 2

0

Sandstone, with abundant included coaly fragments

4 in to 6

Mudstone, dark grey

2 ft to 3

0

Another section is seen in the upper reaches of Strines Dike [SK 2104 8974]:

feet

inches

Shale, silty dark grey

1

0

Shale, black carbonaceous

0 to 2

Coal

0 to 0.5

Mudstone, grey

2

0

Siltstone and silty shale with thin flaggv sandstones

4

0

In Rising Clough [SK 2155 8897] these beds are absent, the marine band resting directly on the Upper Kinderscout Grit. The most complete exposures of these strata on Moscar Moor are in stream banks [SK 2223 8736] 0.5 mile S. of Moscar House:

feet

inches

Shale, silty, passing into fine-grained sandstone

1.5 in to 6

Coal

0 to 2

Seatearth

6 in to 1

0

Siltstone (base not seen)

3

0

At an exposure [SK 2487 8193] north-north-east of Mitchell Field only sandy seatearth 1 ft, lies between the Kinderscout Grit and the R. gracile Marine Band.

Bamford and Hathersage

Between Bole Hill and Scraperlow, the Lower and Upper Kinderscout grits cannot be separated (see above). Sandstone, medium- to coarse-grained with thin siltstone bands and partings 19 ft thick, is exposed in an old quarry [SK 2302 8426]. South of Scraperlow the feature of the Upper Kinderscout Grit is discernible running due south, and crags and blocks of medium- to coarse-grained sandstone form a small scarp 100 to 150 yd E. of Hathersage Booths.

Crook Hill and Win Hill

Approximately 70 ft of the Lower Kinderscout Grit form the two craggy summits on Crook Hill. Outcrops of massive coarse-grained pebbly sandstone occur in 'edges', up to 30 ft high in the north-westerly outlier, and 40 ft in the south-easterly outlier.

The summit of Win Hill is formed by approximately 70 ft of Lower Kinderscout Grit. Residual crags and blocks of mainly medium- to coarse-grained fairly massive sandstone are abundant.

Offerton, Abney and Curbar

The sandstone forming the top of Offerton Moor is considered to be Kinderscout Grit on lithological grounds and from a general consideration of the thickness relations of the underlying Shale Grit. The maximum thickness of this highest sandstone on Offerton Moor is estimated to be nearly 100 ft. Abundant blocks of medium- and coarse-grained sandstone, mainly massive, are present on and under Shatton Edge. In a quarry [SK 2070 8106] east of Shatton Edge, 25 ft of well jointed medium-grained sandstone are exposed. The Reform Stone [SK 2121 8077] is part of a 400-yd long craggy edge of medium- to coarse-grained fairly massive sandstone. A number of outcrops of similar rocks are present in the upper reaches of Dunge Brook [SK 2123 8040] and for 220 yd upstream. In a quarry [SK 2016 8021] 19 ft of mainly massive medium-grained sandstone are exposed. A small outlier of the highest sandstone of Offerton Moor is present on High Low [SK 222 802], and contains a number of small outcrops of medium-grained sandstone, well-bedded and even flaggy in places. G.D.G.

South of Shatton Edge

The Kinderscout Grit forms a tract of moorland sloping gently to the east. A small outlier is also present at Abney Low. On Eyam Moor the grit gives rise to a long dip-slope and this, though broken by faulting near Mag Clough, extends south-eastwards to Knouchley. The best section in this area is at Stokehall Quarry [SK 2365 7693] where grey siltstone with plants 3 ft, overlies buff-coloured coarse sandstone, massive but with micaceous partings, a few small pebbles and some soft ferruginous patches 60 ft. About 15 ft of red-stained coarse sandstone on 5 ft of shale were reported to have been proved below the exposed section.

In the south-east corner of the district the Kinderscout Grit forms an outlier in the small hill east of Calver Sough. The grit thins to some 30 ft on the northern side of Curbar, but thickens again before passing outside the district a quarter of a mile south of this village. I.P.S.

Middle Grit Group Shales below Chatsworth Grit

Glossop to Hayfield

Around Chunal these beds are some 550 ft in thickness, but they thicken southwards to about 720 ft at Hayfield. The most conspicuous features are a lower series of shales with the Reticuloceras gracile, Reticuloceras bilingue early form and Reticuloceras bilingue late form bands and a sandstone up to about 40 ft thick in the middle of the group, the latter traceable south from the latitude of Chunal through Hollingworth Head to Carr Meadow where it thins out.

The lowest bedsMeasured by Mr. C. G. Godwin. are well seen in an exposure [SK 0302 9073] in Long Clough:

feet

Mudstone, lower part micaceous

7

Mudstone, dark, with decalcified bands; Caneyella rugata, Hudsonoceras cf. ornatum, Reticuloceras bilingue early form, mollusc spat

7

Mudstone, grey, with some harder platy bands

8

Mudstone, grey, pyritous

2

Mudstone, grey, with some harder platy bands

4

Mudstone, slightly silty; C. rugata, Dunbarella speciosa, orthocone nautiloid indet., Anthracoceras sp., Reticuloceras gracile, ostracods, fish debris about

4.5

Not exposed

2

Upper Kinderscout Grit

Farther downstream a small inlier of Upper Kinderscout Grit and R. gracile Marine Band is present: the section [SK 0297 9096] is similar to that already described and extends upwards to include the R. bilingue early form horizon. Higher beds are present in a tributary clough [SK 0284 9104] where the R. bilingue late form Marine Band is present, some 60 ft above the R. bilingue early form Band: the band, 3 ft thick, yielded D. cf. speciosa in addition to R. bilingue early form. The Reticuloceras superbilingue Marine Band, about 95 ft higher in the sequence, is exposed 140 yd farther upstream [SK 0271 9098]; it is 2 ft 4 in thick and yielded Myalina ?, Caneyella cf. multirugata, Dunbarella sp., Donetzoceras cf. sigma, Homoceratoides cf. divaricatus, Gastrioceras sp., R. superbilingue. The R. superbilingue Band lies about 45 ft below the sandstone of Hollingworth Head (see above) which forms the head of the clough.

Farther south, the R. bilingue late form Marine Band is exposed in a stream [SK 0332 8951] 140 yd W.N.W. of Carr Meadow: 2 ft of soft shale overlie 6 in of shale with Caneyella cf. rugata, Anthracoceras or Dimorphoceras sp., Hudsonoceras ornatum and Reticuloceras metabilingue Wright. Here some 160 ft of shale separate the overlying sandstone from the Upper Kinderscout Grit and the marine band lies about 90 ft above the base. As the R. superbilingue Band should lie between 20 and 45 ft below the sandstone this section suggests a considerable local thinning in the beds between the two marine bands (to some 40 ft) compared with Long Cough where the thickness is 95 ft. The R. bilingue late form Band is better exposed in the stream [SK 0309 8880] west of Marl HouseSection measured by Mr. Monograptus J. Reynolds.:

feet

Shale, grey, brown-weathering, seen

4.5

Shale, blue-grey, iron-stained, with

thin ironstone bands in lower half

15

Not exposed

2

Shale, dark blue-grey, iron-stained

1

Shale, soft dark blue-grey, 'sulphurous'; Dunbarella cf. speciosa, Anthracoceras sp., Reticuloceras metabilingue, R. cf. bilingue late form; the first-named is common at the base only

5

Between Little Hayfield and Hayfield the lower part of the shale group is concealed by boulder clay. Higher beds are seen on the west side of the stream, and an exposure [SK 0311 8766] near the mill-pond north of Bankvale Mill showed:

feet

inches

Sandstone, hard flaggy

25

0

Shale, poorly exposed

about 18

0

Shale, dark, with C. cf. rugata, cf. Posidonia insignis (Jackson), orthocone nautiloid, Donetzoceras sigma, Gastrioceras sp., Reticuloceras superbilingue, mollusc spat

4

Shale, grey, darker above

1

6

Not exposed

4

0

Shale, soft grey

4

0

The marine band is the Donetzoceras sigma horizon, probably lying a few feet higher than that of Long Clough (see p. 226). About 20 yd south of the above section the uppermost beds are cut out by a fault which throws down 25 ft of well-bedded sandstone with siltstone partings. To the north of the fault the sandstone, which lies at or near the horizon of the sandstone of Hollingworth Head, gives rise to a steep bank above the river for a distance of 350 yd. It is not developed, however, in a small clough west of Little Hayfield where a nearly continuous section of the beds at this horizon shows them to consist mainly of silty mudstones with thin siltstone and sandstone bands.

Hayfield to Chinley

Traced southwards from Hayfield, there is a marked expansion in these beds to about 950 ft at Chinley.

The lowest beds are exposed in a stream [SK 0439 8554] near The Heys:

feet

Shale, grey; C. rugata, Dunbarella speciosa, Anthracoceras or Dimorphoceras sp., Reticuloceras gracile

4.5

Mudstone, sandy micaceous

1

Not exposed (sandy micaceous mudstone exposed in this position 80 yd upstream)

3

Upper Kinderscout Grit

Higher beds are seldom well exposed, though the section in Foxholes Clough base at [SK 0377 8595] shows exposures of silty mudstones with thin sandstones totalling some 200 ft and overlain by the Chatsworth Grit. Farther south the col west of Hills House shows a rather exceptional development of the uppermost two-thirds of the group, three sandstones, each some 20 to 30 ft thick, being developed. These sandstones, however, die out when traced both north and south from the col.

The Otter Brook valley, north of Chinley, shows few exposures, the lower beds being obscured by boulder clay and the higher forming featureless ground on the slopes below the escarpment of the Chatsworth Grit and Rough Rock. An old quarry [SK 0439 8357] north of The Naze shows 8.5 ft of silty mudstone with thin flaggy sandstones.

Whitehough to Chapel en le Frith

South of Chinley these beds maintain their thickness. The most important feature is the incoming of the Roaches Grit a little north of White-hough. The higher beds are exposed on the slopes of Eccles Pike and a good section of the lower is provided by the boreholeDrilled by rock-bit to 224 ft; record from borer's log and examination of cuttings above this depth and from examination of cores below. at Whitehall Works [SK 0355 8202]:

Thickness

Depth

feet

inches

feet

inches

Superficial deposits

14

0

14

0

Roaches Grit: sandstone with two shale bands, 13 ft at 58 ft and 10 ft at 94 ft

110

0

124

0

Mudstone, silty, often finely micaceous with a few thin sandstone and siltstone bands; ironstone nodules in places; Curvirimula ? at 246 ft and from 250 ft 3 in to 251 ft 6 in; plant debris

191

2

315

2

Mudstone, some ironstone; scattered plant debris; fish scales in places; thin pyritous bands near base; Curvirimula ? at 331 ft 9 in

73

10

389

0

Reticuloceras bilingue Marine Band

Mudstone, hard dark platy; Caneyella rugata, Anthracoceras or Dimorphoceras sp., R. bilingue

1

4

390

4

Mudstone, grey, with some ironstone; a 2-in band with Lingula mytilloides at 390 ft 8 in

5

8

396

0

Mudstone, hard dark; Anthracoceras or Dimorphoceras sp., Reticuloceras sp. nov., mollusc spat

7

396

7

Mudstone, grey blocky; rare ill-preserved goniatites; fish debris at 401 ft 8 in

5

11

402

6

Mudstone, hard grey, with a 5-in limestone bullion at 403 ft 6 in;

Dunbarella sp. and mollusc spat

1

2

403

8

Mudstone, grey, with some hard bands, pyritous; fish debris in places

21

10

425

6

Reticuloceras bilingue early form Marine Band

Mudstone, hard dark platy; Anthracoceras or Dimorphoceras sp., mollusc spat

1

0

426

6

Mudstone

1

6

428

0

No core

2

6

430

6

Mudstone, grey, with hard platy bands; Caneyella sp., Dunbarella sp., Anthracoceras or Dimorphoceras sp., cf. Gastrioceras sp., R. bilingue early form, mollusc spat, palaeoniscid scale

9

9

440

3

Mudstone, grey, partly pyritous

8

5

448

8

Reticuloceras gracile Marine Band

Mudstone, hard; Anthracoceras or Dimorphoceras sp., Reticuloceras sp.

4

449

0

Mudstone; fish debris

3

0

452

0

Mudstone, hard, with two thin lenses of limestone; a 10-in bullion at 459 ft 6 in; C. rugata, Dunbarella sp., Anthracoceras or Dimorphoceras sp., R. gracile [evolute form]

14

10

466

10

Mudstone, medium grey to dark; fish debris, Caneyella sp., Anthracoceras or Dimorphoceras sp., mo llusc spat

8

467

6

The Forge Works No. 3 Borehole [SK 0417 8219], at Chinley, proved drift to 50 ft and then "mainly shaly beds" (fide F. W. Cope). Specimens representing the R. bilingue early form Marine Band were found: C. rugata, Anthracoceras or Dimorphoceras sp. and mollusc spat at 109 ft and C. rugata, R. bilingue early form and mollusc spat between 113 ft and 117 ft. The R. gracile Marine Band was recorded as showing C. rugata, Dunbarella sp., Anthracoceras or Dimorphoceras sp., R. gracile and mollusc spat, all from 147 ft. The record of the borehole cannot, however, be regarded as complete, nor the thicknesses of the two marine bands as certain.

The Roaches Grit, 100 ft thick and faulted, forms subdued glaciated features between Bradshaw Hall and Whitehough. It is poorly exposed, though 3 ft of micaceous flaggy sandstone at the base are seen in a road-cutting [SK 0460 8140] near Hallhill Farm. At Whitehough the lower beds were proved in a trench, the base being at [SK 0408 8186], and flaggy sandstones with thin mudstone partings were seen west of this point for a distance of 40 yd. Some 280 ft higher a persistent sandstone about 30 ft thick is present on both north-east and south-east flanks of Eccles Pike; it is exposed behind Eccles House [SK 0354 8156] as sandstone with siltstone partings, 6 ft thick. About 170 ft of shale separate this sandstone from the Chatsworth Grit.

Combs and Dove Holes

In the Combs valley the lower beds are obscured by drift. The Roaches Grit can be traced, though faulted, from Spire Hollins southwards into the axial area of the Longhill Anticline (see p. 326) where it is some 30 to 70 ft. The underlying Corbar Grit, separated from the Roaches Grit by about 150 ft of shale, is developed in the vicinity of Heylee. To thewest of the Longhill Anticline exposures of the Roaches Grit are poor though sandstone near its top is exposed in a stream [SK 0342 7886] at Spire Hollins. A stream section north-west of Heylee shows higher beds, silty mudstones and siltstones with some beds of dark platy shale, extending nearly up to the base of the Chatsworth Grit, though the uppermost beds are faulted out. From a point [SK 032 783] in this section, Jackson (1958, p. 80) records Calamites sp., Lepidophloios laricinus Sternberg, Dunbarella elegans, Posidonia insignis, Orthoceras sp., nautiloid, Gastrioceras spp., Homoceratoides divaricatus and Reticuloceras superbilingue. This horizon appears to lie some 200 ft above the Roaches Grit.

On the eastern limb of the Longhill Anticline the Roaches Grit is well exposed along Ridge Lane. A quarry [SK 0380 7730] here shows 30 ft of coarse sandstone with pebbly bands. The overlying beds, mostly shales with thin sandstones, are seen in the lower part of Pyegreave Brook. Higher up the same brook 6 in of hard flaggy calcareous mudstone is exposed [SK 0488 7806] yielding Anthracoceras or Dimorphoceras sp. and Reticuloceras superbilingue.

At Castle Naze a small exposure [SK 0482 7857] showed dark-weathered shale with Reticuloceras superbilingue. This is at or near the Bull Hills locality where Jackson (1953, pp. 191–2) obtained D. elegans, P. cf. insignis, Gastrioceras spp., Homoceratoides fortelirifer and R. superbilingue. This horizon is only some 30 ft above the Roaches Grit indicating rapid variations in the thickness of the beds in this part of the succession.

The Roaches Grit forms conspicuous features between Ridge Hall and Lady Low. It is developed as one main bed though there is a thin lower leaf which unites locally with it. A quarry [SK 0556 7932] showed 22 ft of medium-grained sandstone, mostly well bedded though more massive in places and with some thin partings of silty mudstone; the undersides of some of the sandstones showed load-casts. Farther east a quarry [SK 0650 7807] near Lady Low shows 40 ft of coarse massive sandstone. South of here the upper leaf of the grit thins, but additional thin leaves come in at a lower level, the whole ranging over some 250 ft of strata. This development continues south on to Brown Edge.

The Reticuloceras gracile Band is exposed in soft shales, some 4 ft thick, in a small clough [SK 0595 7925], 0.25 mile N.N.E. of Ridge Hall. It yielded Dunbarella sp. and R. cf. gracile. The higher part of the clough shows a nearly continuous succession of silty mudstones, siltstones and thin sandstones up to the base of the Roaches Grit. The same band was found in an exposure [SK 0662 7878], 300 yd N.W. of Cowlow farm: 5 ft of dark shale with C. rugata, D. speciosaand R. gracile [evolute form] resting on 2.5 ft of brown-weathered shale. Local thinning is apparent here as only 170 ft of shale separate the R. gracile Band from the Roaches Grit.

A stream section by Blackedge Reservoir shows beds between the Roaches Grit and Kinderscout Grit. The R. gracile Band at the base is not visible but the R. bilingue Band was found [SK 0673 7655] with the following section: shale 2.5 ft, on dark shale, decalcified in lowest 7 in, with R. bilingue 1 ft 7 in, on shale 4 ft. This band lies about 100 ft above the Kinderscout Grit and some 30 to 50 ft above the horizon of the R. gracile Band (see also p. 222). About 30 yd upstream and 30 ft higher in the succession a 3-ft band of dark slightly silty shale yielded R. metabilingue, indicative of the R. bilingue late form horizon. About 300 ft of shale (seen in the upper half as silty mudstone with thin flaggy sandstones) separate this from the lowest beds of the Roaches Grit.

Brown Edge and Longhill

The most complete section in this area is seen in Hogshaw Brook. The R. gracile Band is not exposed, but the R. bilingue early form Marine Band [SK 0599 7423] (on One-inch Sheet 111) consists of 2.5 ft of shale, grey above, blocky pyritous below, with Dunbarella sp. and R. bilingue early form. This band lies some 40 ft above the Kinderscout Grit. About 60 ft higher in the sequence and 150 yd upstream [SK 0596 7434] the R. bilingue Band is exposed (also on One-inch Sheet 111): shale 4 ft on dark decalcified shale with R. bilingue 4 ft, soft dark grey shale 2 ft. Between the latter band and the base of the Corbar Grit (see p. 230) are about 350 ft of shale, the lower half of which is seen in a few exposures near the base, where it is free of silty bands. The upper part is, as elsewhere, composed of silty shales with thin sandstones and siltstones.

The Roaches and Corbar grits form a complex group of sandstones with shale partings, about 600 ft thick in Hogshaw Brook. The group thins northwards with the disappearance of the Corbar Grit; southwestwards the sandstones at the base of the Roaches Grit fail, while those in the upper part coalesce. The sandstones in the Corbar Grit are flaggy, with shale partings in the vicinity of Hogshaw Brook; the Roaches Grit is much more regular in development and it is continuous between Corbar Hill (One-inch Sheet 111) and Brown Edge. A quarry in the Roaches Grit below Lightwood Reservoir [SK 0539 7495] shows well-bedded coarse sandstone 40 ft thick.

Above Lightwood Reservoir the R. superbilingue Marine Band was found in the brook course [SK 0547 7529] with the following section: grey mudstone 3 ft, hard flaggy calcareous mudstone with Promytilus cf. foynesianus, Reticuloceras sp. and palaeoniscid scales 3 in, on grey blocky mudstone 3 in. This section lies within a foot or two of the top of the Roaches Grit and about 280 ft of shale separate it from the Chatsworth Grit.

On Corbar Hill the Corbar Grit is about 220 ft thick and is separated by 450 ft of shale from the overlying Roaches Grit, which is 150 ft thick. This succession holds in a general way for the Longhill Anticline where, however, some splitting and dying out of individual sandstone beds makes the development more complex. Underlying strata are exposed near the axis of the anticline in a stream [SK 0379 7483], 0.25 mile E.S.E. of Longhill Farm:

feet

inches

Shale, grey

2

6

Mudstone, soft grey; Reticuloceras bilingue

1

6

Mudstone, hard dark platy; R. bilingue

5

Mudstone, dark to medium grey, platy; R. bilingue

3

6

Mudstone, hard dark platy calcareous and slightly micaceous; C. rugata, D. speciosaand R. bilingue

4

Mudstone, grey platy slightly micaceous; R. bilingue; D. speciosain a 3-in band 6 in from base

2

0

Shale, soft grey

1

0

On the western side of the anticline the shales between the Roaches Grit and Chatsworth Grit expand greatly, reaching a thickness of some 600 ft. About 380 ft from the base they contain a flaggy sandstone up to 90 ft thick but of limited lateral extent.

Todd Brook Anticline

In this area the group reaches its maximum development, some 1500 ft in the area south of Kettleshulme, though to the north of that place it is about 1100 ft thick. The beds are not usually very well exposed and the sandstone features are smoothed by glacial action.

The lowest beds, a few feet above the Kinderscout Grit, are seen in a stream [SJ 9890 7769] near Dunge Farm:

feet

Shale, grey

10

Shale, decalcified fossiliferous

0.25

Shale, 'sulphurous'

2

Shale, dark decalcified, with C. rugata, D. speciosa, Anthracoceras sp. and R. gracile

2.5

Shale, grey finely micaceous

About 40 yd upstream [SJ 9893 7768] the R. bilingue early form Marine Band occurs:

feet

Shale, grey 'sulphurous'

2

Shale, dark decalcified ; Caneyella sp.

and R. bilingue early form

2.5

Shale, soft pale

This band lies about 30 ft above the R. gracile Band and 180 ft below the Corbar Grit.

On the western limb of the anticline much of the shale between the Corbar and Kinderscout grits was formerly exposed in two streams south-east of Lamaload; the sections now lie beneath Lamaload Reservoir. One [SJ 9729 7479] showed 3 ft of dark grey shale on black shale with C. rugata, Anthracoceras or Dimorphoceras sp. and R. bilingue. Farther downstream [SJ 9727 7492] a disturbed section in dark shales yielded Homoceratoides sp. and R. bilingue late form (Taylor and others 1963, pp. 6–7). A section in a tributary clough [SJ 9731 7513], now also flooded, showed black shale on soft black shale with goniatites 1 ft 6 in, on dark grey shale 8 ft; the horizon is that of R. bilingue.

In the northern part of the anticline the beds between the Roaches–Corbar group of grits and the Kinderscout Grit are poorly exposed. An exposure [SJ 9818 8119] in Browside Clough shows:

feet

Shale, dark

29

Not exposed

4

Shale, dark

3

Not exposed

1

Shale, dark decalcified; Caneyella ?, Posidonia sp. and R. bilingue

2

Shale, dark, pyritous in places

18

The marine band lies some 380 ft below the Roaches Grit, the Corbar Grit being absent (see below).

The Corbar Grit and Roaches Grit show a variable development around the Todd Brook Anticline. Both grits are readily recognizable in most places though each is much split. The Corbar Grit consists of a variable group of thin sandstone bands (a typical section in Kirby Clough [SJ 990 780] shows three such sandstones) some 300 ft thick in the central and southern part of the anticline, thinning to 90 ft at Kettleshulme and absent in the north in the nose of the anticline around Bailey's Farm. The sandstones are more flaggy than those in the Roaches Grit though on the western limb more massive and less variable beds occur; the Roaches Grit, separated from the Corbar Grit by some 250 ft of shales, mostly silty, is developed as a coarse massive sandstone, 250 ft thick at Kettleshulme. It splits both to north and south of this locality (two beds being present at Kirby Clough). On the eastern limb of the Anticline the Roaches Grit dies out southwards near Green Stack, but on the western limb it shows a more consistent arrangement, though locally split into as many as three separate leaves.

The Corbar Grit was proved in a series of boreholes for the cut-off trench for Lamaload Reservoir. The deepest of theseCores examined by Dr. A. A. Wilson. [SJ 9694 7519] showed sandstone to 70 ft, mudstone to 74 ft 6 in, sandstone to 79 ft 6 in, mudstone to 92 ft, sandstone to 125 ft, siltstone to 172 ft and mudstone to the bottom of the hole at 208 ft.

The shales lying between the Roaches and Chatsworth grits call for little comment. The thickness varies from about 400 ft at Kettleshulme to 500 ft near Dunge Farm. With the dying out of the Roaches Grit in the southeast part of the anticline the thickness of the shale group between the Corbar Grit and Chatsworth Grit increases correspondingly to about 700 ft. These beds are well exposed in stream sections near Thursbitch [SJ 9925 7513] and consist of silty mudstones with thin flaggy sandstones and siltstones. I.P.S.

Bradfield and Moscar

In this area the presence of the Heyden Rock allows the beds between the Kinderscout Grit and Chatsworth Grit to be described under three headings as below.

Shales with Reticuloceras gracile Marine Band at base. Between Bradfield Moors and Moscar Moor these beds thin southwards from 120 ft to approximately 60 ft and comprise shales and silty shales succeeded by siltstones with very thin sandstone bands. The R. gracile Marine Band varies from 5 to 10 ft in thickness, and consists of dark grey, rarely black, shale and mudstone, with abundant goniatites.

In the south bank of the stream [SK 2330 9289] nearly a mile N. by W. of Hallfield, the marine band is 10 ft thick and contains Caneyella sp., D. speciosa, Anthracoceras or Dimorphoceras sp. and R. gracile. Good exposures of fossiliferous shale also occur in the east bank of the stream west of Bole Edge Plantation, where, for example [SK 2259 9200] 6 ft of dark grey shale contain L. mytilloides, C. rugata, Dunbarella sp., Anthracoceras or Dimorphoceras sp., R. cf. gracile and Reticuloceras gracile late form. The marine band also crops out 0.75 mile to the south-south-west at the junction of two streams [SK 2214 9100]. One of the original localities from which this marine band was described by Bisat (1924, p. 117) is on the northern side of Raddlepit Rushes, in Strines Dike [SK 2104 8974] where the band is 5 ft thick and yields C. rugata, D. speciosa, Anthracoceras or Dimorphoceras sp. and R. gracile late form. Similar faunas have been obtained from exposures in Rising Clough [SK 2168 8886]; [SK 2171 8882]; [SK 2206 8814]. On Moscar Moor the lowest 2 ft of the marine band are exposed in a stream [SK 2223 8736] where Dunbarella sp. and R. gracile late form have been found.

The strata overlying the R. gracile Marine Band are well exposed in the stream west of Bole Edge Plantation. On the east bank [SK 2228 9166], siltstone 8 ft, overlies silty shale 8 ft, on shale 22 ft. The east bank of Strines Dike contains frequent outcrops of these beds. At [SK 2176 9058] 600 yd S.E. of Foulstone Delph, 55 ft of shale and silty shale are exposed, and 300 yd to the S.W. [SK 2155 9040] the succession is: siltstone and silty shale 3 ft, fine-grained flaggy sandstone 6 ft, silty shale 8 ft, siltstone 1 ft 6 in, on shale, silty near the top, 40 ft. In the borehole [SK 2349 9173] at Lane Head Farm near Hallfield (pp. 372–3) 62.5 ft of shale were recorded between the Heyden Rock and Kinderscout Grit. Small ironstone nodules 0.5 to 2 inches in diameter are present in the shales about 10 ft above the top of the R. gracile Marine Band, some of them with pyrite centres, and at one locality [SK 2114 8989] nodules from a band lying 7 ft above the stream bed contain fish debris.

Heyden Rock

Between Bradfield Moors and Strines Moor the Heyden Rock is 80 to 100 ft thick, but it thins considerably farther south and cannot be traced beyond Moscar Fields. Residual blocks of medium- to coarse-grained sandstone, locally pebbly, are scattered over the northern part of Bradfield Moors, but in small quarries in the northwestern part of Bole Edge Plantation, nearly 0.75 mile N.N.W. of Hallfield, the sandstone varies between coarse-grained massive, and fine-grained thin-bedded and flaggy, with some false-bedding. The borehole near Hallfield, referred to above, commenced near the top of the Heyden Rock and penetrated 82.5 ft of sandstone before passing down into shales. In the deep gorge of Strines Dike [SK 224 907], outcrops indicate that the lower part of the Heyden Rock is medium- to coarse-grained massive or thick-bedded, but towards the top becomes medium- to fine-grained, well-bedded and, in places, even flaggy. A temporary excavation on the northern flank of the Strines Dike gorge [SK 2256 9071] revealed the following sectionMeasured by Mr. C. G. Godwin. near the top of the Heyden Rock:

feet

inches

Sandstone, fine-grained

2

0

Silty mudstone and siltstone about

11

0

Sandstone, fine-grained flaggy

4

Sandstone, fine- to medium-grained, with abundant casts and moulds of Carbonicola spp.

3

Sandstone, medium- to coarse-grained

4

0

Blocks of sandstone containing Carbonicola spp.are also present in walls in the area around Strines Inn [SK 2227 9062]. Small craggy outcrops and abundant residual blocks of medium to coarse sandstone, mainly well-bedded or gently false-bedded, occur along the western edge of Strines Moor. Farther south medium-grained sandstone 11 ft is exposed in a quarry [SK 2227 8848]. In a stream [SK 2251 8756], 690 yd S.33°E. of Moscar House, and for 40 yd upstream small exposures indicate that the Heyden Rock consists of 15 to 20 ft of sandstone, fine-grained flaggy and micaceous, with thin bands and partings of siltstone and silty shale. The feature formed by the Heyden Rock is indistinct in this locality, and it disappears some 400 yd south of Moscar Fields. G.D.G.

Beds between Heyden Rock and Chatsworth Grit

Between Woodseats and Moscar Moor these beds are 200 to 275 ft thick and are mainly silty shales with some siltstones and two thin sandstones. The lower of these, some 20 ft thick and 60 ft above the Heyden Rock, forms the conspicuous dip-slope on which Woodseats is situated, but it dies out rapidly to the south-west. About 60 ft higher lies the upper sandstone of similar thickness; the intervening shales contain, in their middle, the Reticuloceras superbilingue and Donetzoceras sigma horizons. The latter was seen in the river bank between Strines and Dale Dike reservoirs [SK 2336 9066]Section measured by Mr. J. Pattison.:

feet

inches

Shale, dark grey, rusty-weathered

10

0

Shale, black 'sulphurous'; Caneyella rugata, Donetzoceras sigma and mollusc spat

9

Shale, dark grey, rusty-weathered

5

0

Shale; Lingula sp. and C. rugata

1

Shale; L. mytilloides at base

6

I.P.S.

South of Sugworth Hall silty mudstones with thin siltstone and sandstone bands succeed the Heyden Rock and have been seen in a number of temporary excavations. Unidentifiable fragments of goniatites and posidoniids were noted in a temporary section [SK 2244 8872] estimated to lie 10 to 20 ft above the Heyden Rock, at the horizon of the Reticuloceras bilingue late form Marine Band.

A thin flaggy sandstone is locally developed on the slopes west of Bents Farm, probably about 60 ft above the Heyden Rock and is also exposed in Pears House Clough [SK 2247 8989] near where it is faulted against higher shales containing R. superbilingue. The succeeding 100 ft or more of shales and mudstones contain the R. superbilingue Band 10 to 40 ft above, and the D. sigma Band 70 to 90 ft above, their base. Masses of slipped shale containing R. superbilingue are present on the northern bank of Strines Reservoir [SK 2287 9061].

From the upper 2 ft of a 13-ft shale outcrop in Pears House Clough [SK 2252 8989], the following fossils were collected: Caneyella sp., Posidonia sp., Gastrioceras sp. nov., Homoceratoides fortelirifer, Ht. aff. divaricatus and R. superbilingue. This exposure is at, or very near, the locality mentioned by Davies (1941, pp. 241–4) and by Pulfrey (1934, pp. 254–64). The same band also crops out 190 yd lower down the clough and 9 ft up on the south bank [SK 2271 8992], and a similar fauna was also found near Bradfield (Eden and others 1957, p. 19). In the banks of the stream east of Bents Farm the R. superbilingue fauna has been found at several localities [SK 2277 8924]; [SK 2278 8908]; [SK 2282 8900]. The most northerly of these outcrops is believed to be downfaulted with respect to the other two, but assuming that no slipping has occurred the fauna appears to be spread through 30 ft of strata (see p. 180). Approximately 40 to 50 ft above, in the same stream [SK 2283 8896], Caneyella sp. and D. sigma occur in an 8-ft bed overlying 8 ft of unfossiliferous shale, supporting the impression that in this area the interval between the R. superbilingue and D. sigma bands has expanded to 50 ft or more (Pulfrey 1934, p. 259). The higher beds in this stream are silty shales and siltstones with a few thin hard sandstone bands, succeeded by a thin flaggy sandstone estimated to be about 20 ft thick. The R. superbilingue-Ht. fortelirifer fauna was collected from a temporary section farther south [SK 2267 8832], and from extensions of this section to the south-east. The beds above the R. superbilingue Band contain a few feet of fine-grained flaggy sandstone exposed in quarries [SK 2279 8836] 0.25 mile N.W. of Moscar Lodge, where it forms a distinct feature. The succeeding strata up to the Chatsworth Grit consist of silty mudstones, siltstones and thin hard sandstones. G.D.G.

Hathersage to Curbar

West of Stanage Edge, about 400 ft of strata separate the Kinderscout Grit from the Chatsworth Grit; these beds are obscured by head. Farther south these beds thin to 250 ft and consist mainly of shale, though the Ashover Grit makes its appearance near the south-eastern corner of the sheet at Curbar.

To the east of Hathersage the lowest of these beds are exposed in a stream [SK 2487 8192], 210 yd N.N.E. of Mitchell Field:

feet

Shale, black; Caneyella sp., R. gracile

3

Seatearth, sandy

1

Sandstone, hard; top of Kinderscout Grit

Some 250 yd upstream dark grey mud stone with ironstone nodules overlies dark unfossiliferous shale of marine aspect, possibly at or near the R. bilingue horizon. The uppermost beds are exposed in a landslip-scar at Callow Bank [SK 2519 8229]:

feet

Sandstone, massive medium-grained (Chatsworth Grit, main bed)

15

Shale, dark, poorly exposed

6

Sandstone

1

Mudstone, grey silty, poorly exposed

12

Sandstone, massive, lower leaf of Chatsworth Grit

10

Mudstone, grey silty

4

Sandstone, soft fine-grained

2

Shale, dark, fossiliferous in top 4 in and lowest 3 in; Zygopleura sp. and Donetzoceras sigma

5.5

Shale, dark

8

Farther south no sections of these beds are available until Burbage Brook is reached. Here, a section [SK 2514 7910] in Yamcliff Wood, showed:

feet

Sandstone (lower leaf of Chatsworth Grit, see p. 236)

Not exposed

30

Shale, dark pyritous; Lingula sp. and D. sigma in 3-in band at 6 in from top; rare Lingula sp. 3 ft from base

9

Not exposed about

15

Shale, grey

12.5

Shale, soft dark grey 'sulphurous'; C. multirugata, Dunbarella sp. [juv.], R. superbilingue, D. sigma

1.5

The upper band, with Lingula sp. and D. sigma, evidently represents the D. sigma horizon while the lower, with D. sigma and R. superbilingue, is the R. superbilingue horizon.

The Donetzoceras sigma Band is also exposed farther downstream, near Grindleford station [SK 2503 7869]:

feet

inches

Shale, dark

6

Shale, soft grey

5

6

Shale, black with a 1-in band containing C. multirugata and D.

sigma

3

Mudstone, grey

6

At Curbar, just within the district, the Ashover Grit makes its appearance, in the middle of the shale between the Kinderscout Grit and the Chatsworth Grit. It is poorly exposed, but thickens to the south and south-east to reach its normal development in the Chesterfield district (Smith and others 1967, pp. 67–72).

Chatsworth Grit

East of the River Goyt

Near the northern edge of the district, the Chatsworth Grit is a yellow-brown medium-grained sandstone about 80 ft thick near Plainsteads, though thinning locally, as at Simmondley. At the latter locality a lower leaf appears and this has been included by J. V. Stephens within the outcrop of the grit postulated beneath the drift of the Glossop valley. An exposure [SK 0241 9149] near the middle of the outcrop of the grit, shows 2 ft of ganister with rootlets and Stigmaria on 1.75 ft of creamy saccharoidal siliceous sandstone (see also p. 181). The grit forms a broad outcrop on Matley Moor, where it is of moderately coarse grain. A quarry [SK 0261 9040] near Knorrs shows coarse sandstone with some red staining, which was also found [SK 0248 8968] near Matleymoor Farm. To the east of the latter locality a lower leaf of the grit is present for three-quarters of a mile along the outcrop.

To the west of Cown Edge, the record of the working of the Simmondley Coal at Coombes Pit (see p. 236) allows the presence of an outcrop of Chatsworth Grit to be inferred, though it is entirely under drift.

At Birch Vale the Garrison Bleach Works No. 2 Borehole [SK 0151 8682] proved the Chatsworth Grit to be 55.75 ft in thickness with its base at 200 ft depth. It thickens eastwards and is split into two leaves between Birch Vale and Hayfield. At Birch Quarry [SK 0302 8690] the lower leaf, some 60 ft of yellow-brown rather massive coarse sandstone with some cross-bedding, is worked.

To the west of Hills House, impersistent shale partings are present towards the base of the Chatsworth Grit. Followed southwards the feature of the grit becomes inconspicuous but it stands out again at The Naze [SK 0414 8348], owing to a striking change in the lithology to a massive coarse cross-bedded sandstone with scattered quartz pebbles, 50 ft thick. The grit has been much quarried at Buxworth and a section [SK 0279 8195] shows 40 ft of coarse-grained reddened sandstone. Farther to the south-east the Chatsworth Grit forms the prominent feature of Eccles Pike, the top of which shows some 18 ft of coarse pebbly sandstone with dark red staining in places.

Between Tunstead and the southern edge of the district the Chatsworth Grit gives a well-marked craggy scarp. A typical section [SK 0306 7856] near Thorny Lee shows 30 ft of coarse red-stained sandstone, with bands of pebbles up to 0.75 inch in diameter. The grit is also well exposed in an old road-cutting at Wainstones [SK 0280 7715] and at Rake End [SK 0257 7586]. Near the latter locality a lower leaf of sandstone appears beneath the Chatsworth Grit and joins the main bed to the south.

To the east of the main outcrop the Chatsworth Grit forms the conspicuous outlier of Combs Moss, where it is about 130 ft thick on the western side, though it probably thins eastwards. The lower part of the grit varies to some extent owing to the local development of thick flaggy beds beneath the upper coarse massive part; a typical section [SK 0390 7642] of this type lies north of Combs Edge:

feet

Sandstone, massive coarse

32

Sandstone, flaggy micaceous with partings of micaceous siltstone and shale; partings showing deep red staining

75

A section [SK 0527 7840] at Castle Naze shows 55 ft of pink-stained massive coarse sandstone, pebbly in places and with erosional base, on pink and yellow variegated well-bedded coarse- to medium-grained sandstone 9.5 ft.

In the central part of the Goyt Trough the Femilee No. 1 Borehole [SK 0124 7823] proved the Chatsworth Grit from 349.5 ft to the bottom of the hole at 476 ft. Except for the top 4.75 ft and lowest 14.75 ft, which were finer-grained and more flaggy, it was coarse and massive, frequently red-stained and with darker hematitic patches. Pebbly bands were present between 435 ft and 461.25 ft.

West of the River Goyt

To the west of Mellor the Chatsworth Grit forms a small outcrop in the stream at Cataract Bridge (see also p. 238). Faulted [at 9712 8878] against Woodhead Hill Rock on the west, it is present upstream to the east for a distance of 150 yd as a yellow-brown medium-grained sandstone. A larger outcrop, much obscured by drift, is present near the River Goyt between Bottom's Hall and Hague Bar. It is exposed in several streams north-east of Strines, for example south of Windybottom Farm [SJ 9733 8702] and for 190 yd upstream, the exposures covering nearly the full thickness: here it is hard and siliceous in its lower part and more flaggy above. The borehole at Grove Mill [SJ 9942 8506], New Mills, proved a thin coal on 43.5 ft of sandstone, with base at 240 ft, at this horizon.

The Chatsworth Grit was quarried [SJ 9762 8402] in the faulted axial area of the Todd Brook Anticline near Stoneridge, where 15 ft of pink-brown medium-grained feldspathic sandstone are seen. The total thickness of the grit in this area is some 140 to 200 ft, but it forms subdued features often much modified by glaciation. On the western limb of the anticline the grit passes outside the district south-west of Charles Head. On the eastern limb it is flaggy and fine-grained between Cliff and Todd Brook. Farther south, between Claytonfold and Fivelane Ends, splitting and faulting tend to obscure the outcrop. To the south-east of Fivelane Ends it becomes coarse-grained, giving rise to the sharp feature of Windgather Rocks, south of which a roadside quarry [SJ 9952 7809] shows 35 ft of yellow massive coarse feldspathic sandstone with bands of small pebbles, some cross-bedding and patchy reddening in places. Still farther to the south it forms a marked escarpment and dip-slope. A section [SJ 9953 7633] near Oldgate Nick shows 52 ft of pink coarse feldspathic sandstone with bands of pebbles of up to 0.75 in diameter and strong cross-bedding.

Eastern area

In the north-eastern corner of the district, the Chatsworth Grit (see also p. 181) is variable in character. To the northeast of Walker House it is well developed, though split into two leaves, the whole totalling some 60 ft. A section [SK 2519 9171] near the base, south-east of Walker House, shows 23 ft of yellow-brown flaggy sandstone. The bed thins rapidly south-westwards and in much of Bradfield Dale it is only 25 ft thick and forms very subdued features. It thickens again south-west of Holes Clough [SK 236 905], though from here to Moscar Lodge it maintains its fine-grained flaggy character. To the south of Moscar Lodge it again becomes coarse-grained and massive, as in the Rivelin valley (Eden and others 1957, p. 19), and forms strong features. To the east of the escarpment the grit forms a broad outcrop on Hallam Moors. I.P.S.

Between Stanage End and High Neb the Chatsworth Grit produces a bold escarpment showing up to 60 ft of coarse massive sandstone with bands of quartz pebbles up to (rarely) 1 in diameter. The total thickness hereabouts is around 80 ft, but the lowest beds are obscured. The sandstones are finer-grained at the top. False-bedding is fairly common. A lower leaf, up to 40 ft thick, of flaggy sandstone, makes its appearance near Overstones Farm and forms a broad outcrop north of Higger Tor [SK 256 820], where the coarser massive upper leaf forms an outlier. LP.S., G.D.G.

To the south-east of Hathersage the Chatsworth Grit gives rise to the strong scarp of Millstone Edge. A section in Grey Millstone Quarries [SK 248 805] shows 60 ft of coarse grey sandstone with sporadic conglomeratic bands. Farther south the grit forms the strong escarpments of Froggatt Edge, Curbar Edge and Baslow Edge. The section in Burbage Brook given on p. 233 is continued upwards as follows:

feet

Chatsworth Grit, main leaf

Not exposed

60

Sandstone, massive

30

Mudstone, grey, part exposed about

25

Sandstone, massive, base in stream at [SK 2519 7916]

15

The two lowest sandstones are shown on the map as the lower leaf of the Chatsworth Grit. It is present in the valley of Burbage Brook and is probably identical with the lower leaf of Higger Tor, though the outcrops are not continuous.

Beds between Chatsworth Grit and Gastrioceras cancellatum Marine Band

These beds, lying near the base of the shale slack between the Rough Rock and Chatsworth Grit, are often poorly exposed and in many places the position of the Gastrioceras cancellatum Band can only be inferred. Moreover, the presence in places of a sandstone close above the Chatsworth Grit leads to confusion where exposures are not good.

Glossop to Hayfield

At Simmondley, the Simmondley Coal, 24 to 30 in thick, lies about 40 ft above the Chatsworth Grit. Many shafts were sunk to the coal between points west and south of Simmondley village. The G. cancellatum Band probably lies a short distance above the coal as material from it was noted by J. V. Stephens (in Bromehead and others 1933, p. 70) on the tip from a shaft to the coal at Gamesley, just north of the district boundary. Farther south a sandstone lying between the Simmondley and Ringinglow coals and up to 25 ft thick is developed from a point 0.5 mile N. of Plainsteads to Cloughhead [SK 0160 9043]. A section [SK 0203 9110] shows the Ringinglow Coal horizon: sandstone 6 in, coal 2 in, seatearth (close above Chatsworth Grit) 2 ft. The Simmondley Coal was worked as late as 1931 by adit at Cown Edge Colliery [SK 0188 9104] under the name 'Two Sheds'; it was here 24 in thick. Farther west, at Coombes Colliery [SK 0158 9212] it was 30 in thick. To the south-east of Lantern Pike, a coal, probably the Ringinglow, was worked from a shaft [SK 0264 8764] near Higher Cliff. A stream section [SK 0256 8730] near Lower Cliff shows a small thickness of flaggy sandstone on 3 ft of ganister, the whole a short distance beneath the Ringinglow Coal. The presence of the sandstone indicates that here the coal and ganister do not belong to the same cycle, an additional small cycle having made its appearance. This accords with the information from the Rod Moor No. 3 Borehole (Eden and others 1957, p. 213) where 7.5 ft of dark sandy shale separate the Ringinglow Coal from the top of the Rivelin (Chatsworth) Grit. The Garrison Bleach Works No. 2 Borehole (see p. 366) showed 30 in of 'black shaly coal' at 136 ft, lying 8.25 ft above the top of the Chatsworth Grit, no other coal being recorded.

Chinley

North of Chinley a thin Simmondley Coal was seen in the following section [SK 0394 8377] by the tram-track from Cracken Edge Quarry:

feet

inches

Mudstone, brown silty about

3

0

Mudstone, black, with fusain fragments about

1.5

Coal

1

Seatearth, with rootlets and other plant debris

2

6

Not exposed

2

0

Sandstone

8

0

The sandstone, up to about 20 ft thick and lying 15 to 20 ft above the Chatsworth Grit, is present for some 700 yd south of this locality.

On the western slopes of Eccles Pike a sandstone, up to 40 ft thick, is present between the Simmondley Coal and the calculated position of the G. cancellatum Marine Band. This may be a western continuation of the Redmires Flags.

South of Whaley Bridge

In this part of the eastern limb of the Goyt Trough exposures are usually lacking. The Ringinglow Coal was formerly worked near Rake End [SK 0241 7575]. Near the southern boundary of the district a section [SK 0196 7453] in a tributary of Wildmoorstone Brook showed:

feet

inches

Sandstone, ? in situ

Mudstone, grey silty, with thin sandstone bands

6

0

Mudstone, soft grey

2

1

Ringinglow Coal, 23 in

1

11

Seatearth, grey, darker at top

6

Seatearth, buff rusty-weathering, becoming silty downwards

2

4

Sandstone, buff fine-grained (top of Chatsworth Grit)

2

6

The coal was formerly worked by bell-pits at this locality.

Fernilee No. 1 Borehole [SK 0124 7823], near the axis of the Goyt Trough, proved the most complete section of these beds in the area:

Thickness

Depth

feet

inches

feet

inches

Gastrioceras cancellatum Marine Band (see p. 240)

288

9

Mudstone, pyritous in places; fish debris in lowest 7 ft 7 in

22

1

310

10

Mudstone, medium to dark grey often platy, pyritous in places; Planolites sp., Lingula mytilloides, productoid fragment, Anthracoceras sp. and mollusc spat

7

7

318

5

Mudstone, dark carbonaceous; Sanguinolites sp.

1

318

6

Mudstone, dark carbonaceous; some plant debris; Curvirimula belgica at 319 ft 5 in to 320 ft 6 in

2

6

321

0

SIMMONDLEY

Coal 2 in

Cannel 7 in

Coal 6 in

Mudstone 8 in

Coal, dirty 1 in

2

0

323

0

Siltstone, pale hard banded

8

323

8

Sandstone, hard flaggy siliceous

2

0

325

8

Siltstone and silty mudstone, banded

5

7

331

3

Sandstone, banded flaggy

6

9

338

0

Mudstone, grey silty; Naiadites sp. [juv.]at 338 ft 6 in

1

0

339

0

Siltstone, dark flaggy micaceous

1

2

340

2

Mudstone, banded silty, with thin siltstone bands; plant debris

7

0

347

2

Mudstone, grey blocky, pyritous at base

1

10

349

0

RINGINGLOW

Coal (wash only) about 3 in

3

349

3

Chatsworth Grit (see p. 235)

Near Errwood Hall much of this group of strata is well exposed. A section [SK 0012 7562], 1180 yd N.39°W. of the site of the hall, showed the Ringinglow Coal in the following section: soft grey shale 1 ft 4 in, coal 19 in, soft grey clay 6 in. Between here and the southern edge of the district the beds between the Ringinglow and Simmondley coals, some 25 ft thick, maintain a constant character with a few feet of shale at the base and the remainder sandstone. The Simmondley Coal is variable, a section [SK 0039 7533], 0.25 mile N.W. of Errwood Hall, showing coal 8 in on dirty coal 7 in. Farther south [SK 0048 7501] the lower leaf passes into carbonaceous mudstone:

feet

inches

Gastrioceras cancellatum Band

Shale, soft grey

4

0

Shale, grey platy 'sulphurous', with some ironstone nodules

6

Shale, soft grey finely micaceous

3

0

Shale, hard dark finely micaceous platy

11

SIMMONDLEY

Coal, dirty 5 in

5

Mudstone, dark carbonaceous

4

Mudstone, dark finely micaceous

4

Shale, grey-brown, silty

1

0

Sandstone, flaggy

3

10

Mudstone, silty with siltstone bands

6

0

Sandstone, flaggy

To the south-west of Errwood Hall the Simmondley Coal was worked until 1933 at Castedge Colliery, where it was 15 in thick, under the name 'Little Mine'.

Combs Moss

The Ringinglow Coal and a small thickness of the overlying beds are present as an outlier on the eastern part of Combs Moss. A section in "one of the streams" was given by Hull and Green (1866, p. 61): black shale on coal 10 in, on "light grey underclay with lumps of raddle" 2 ft, resting on Third [Chatsworth] Grit. The coal was worked by bell-pits at the northern and southern ends of the outlier. Overlying the coal are some 10 ft of shale, above which are flaggy sandstones, also 10 ft thick, forming the highest beds in the outlier.

Marple and New Mills

At Cataract Bridge (see also p. 235) an exposure [SJ 9712 8877] in the stream shows the Ringinglow Coal, 12 in, on sandy seatearth overlying the Chatsworth Grit. At Strines an exposure [SJ 9759 8688] in a stream north of Greenclough Farm shows no coal at this horizon but a thin ganister-like sandstone a short distance above the Chatsworth Grit.

Near New Mills, the Grove Mill Borehole (see also p. 366) showed the following section of these beds, below the probable horizon of the Simmondley Coal:

Thickness

Depth

feet

inches

feet

inches

Shale, etc.

160

0

160

0

Sandstone

32

0

192

0

Shale

2

0

194

0

Ringinglow Coal 12 in

1

0

195

0

Seatearth

1

6

196

6

Top of Chatsworth Grit

West of the Goyt Trough

Near the axis of the Todd Brook Anticline an exposure [SJ 9773 8168], west of Handleybarn, showed the following section:

feet

Shale, grey weathered

1.5

Ringinglow Coal smut 12 in

1

Seatearth, grey and purple mottled

2

Top of Chatsworth Grit

The shale at the top of the section is thin and is succeeded by about 30 ft of sandstone which dies out rapidly southwards and also around the nose of the anticline. In Mather Clough 20 ft of shale, part exposed, lie between the top of the sandstone and the Gastrioceras cancellatum Band (see p. 241).

Just south of Todd Brook, a stream [SJ 9982 8045], 270 yd N.E. of Gap House, showed the Ringinglow Coal in the following section: sandy mudstone with thin sandstones 8 ft, coal 16 in, hard ganister with rootlets and carbonaceous streaks 8 in. A short distance above this section lies a sandstone extending upwards to the horizon of the Simmondley Coal (which is not exposed). This sandstone is a constant feature over much of the western side of the Goyt Trough. It is split between Green Head Farm and Needham Farm.

A coal smut in the position of the Ringinglow was seen in the side of the track [SJ 9955 7888] leading to Blackhillgate. To the south, sandstone occupies nearly the whole thickness of the beds between the Ringinglow and Simmondley coals, and, together with the Chatsworth Grit, forms a well-developed composite dip-slope. The Simmondley Coal was formerly worked in an adit in Mill Clough [SK 0016 7802]. The section at this locality (see also pp. 241–2) is:

feet

inches

Gastrioceras cancellatum Band

Shale, dark, with ironstone bands and lenses

17

6

Obscured (including position of Simmondley Coal)

3

0

Seatearth, siliceous with rootlets

1

5

Sandstone, hard siliceous

seen 6

On the western limb of the Todd Brook Anticline the Ringinglow Coal was formerly worked by adit [SJ 972 793] near Charles Head. Here, as on the eastern side of the anticline, the measures between the Ringinglow and Simmondley coals contain a sandstone which appears half a mile north of Charles Elead and continues south-westwards beyond he district boundary. The Simmondley Coal was worked here [SJ 9721 7937] about 1952 with the following section: grey sandstone 4 ft, brown sandy shale 6 ft, bright coal 17 in, soft seatearth.

North-eastern area

On the north-eastern margin of the district a great expansion of these beds takes place, some 120 ft being present in Bradfield Dale. The Ringinglow Coal, as elsewhere, lies at the base and coal debris at this horizon was seen in Holes Gough [SK 2366 9053]. Some 90 to 100 ft of shale separate the coal from the Redmires Flags, 20 to 30 ft thick, which underlie the Gastrioceras cancellatum Band. Farther south the coal was stated by Green and Russell (1878, p. 41) to have been 12 in thick in an adit [SK 2337 8932] near Moor Lodge.

At Lee Bank [SK 231 901] the Redmires Flags are faulted out and to the south, where beds at this horizon reappear between Moor House and Hollow Meadows, they are absent. They reappear, though in an attenuated form, a short distance east of the district (Eden and others 1957, p.21). At Hollow Meadows, a thin coal, in the position of the Simmondley, is exposed in a small stream [SK 2419 8788]: coal smut 2 in, black carbonaceous shale 3 in, on grey seatearth with rootlets 9 in.

The maximum development of the strata, about 140 ft, is reached between Brown Edge and White Path Moss. The lowest beds, with the Ringinglow Coal, were seen at several places in and around Oaking Clough. A section [SK 2468 8610] in the stream 1300 yd N. 19°E. of Stanedge Lodge, showed: shale, with Lingula mytilloides at 9 in from base, 1 ft, on coal a few inches. This is the locality described by Pulfrey (1934, p. 258). A better section of the Ringinglow Coal is exposed a quarter of a mile to the north-west [SK 2425 8632]: grey shale 3 ft, dirty coal at least 12 in, grey seatearth about 3 ft, on top of Chatsworth Grit. Farther south-west [SK 2338 8588] the coal thickens to 24 in.

The Redmires Flags form a well-marked scarp on Brown Edge (see also pp. 182–3) and a scarp and dip-slope on High Lad Ridge. Farther south much of the outcrop of these and the underlying beds is obscured by peat. The only exposure of note [SK 2434 8513], 0.75 mile S.S.E. of High Lad Ridge, shows 6 ft of flaggy sandstone.

A stream [SK 2566 8321] near Cowper Stone, shows abundant loose blocks of ganister representing the seat of the Ringinglow Coal.

Rough Rock Group

Beds between Gastrioceras cancellatum Marine Band and Rough Rock
Glossop to Long Hill

To the south of Simmondley this group of shales, about 180 ft thick, is poorly exposed. It is also present, though much concealed by landslip, in the low ground west of down Edge.

To the north of Rowarth an exposure [SK 0161 8984] in the stream shows the Gastrioceras cumbriense Band:

feet

inches

Shale, grey soft

1

6

Shale, hard dark platy

1

0

Shale, pale grey soft 'sulphurous'

1

4

Not exposed

1

6

Shale, pale grey

6

Shale, soft, decalcified in top 6 in; hard below; Caneyella multirugata, Dunbarella sp., Anthracoceras sp., Gastrioceras crenulatum, G. cumbriense

1

6

This band lies about 80 ft above the G. cancellatum horizon. Farther downstream higher beds come in; these become more arenaceous [SK 01588951] as the base of the Rough Rock is approached.

Between Rowarth and Birch Vale, the thickness varies from 230 to 260 ft, with the local appearance of sandstones either joining with, or just below the Rough Rock.

From Birch Vale to Chinley the beds are about 170 ft thick, but there are no exposures of note. On the western slopes of Eccles Pike they thin to about 130 ft and a thin sandstone is locally present at the top. Farther to the south on the eastern flank of the Goyt Trough good exposures of these beds are also lacking. Near Rake End, however, Cope (1946, p. 171) records a 6-ft contorted band of shale overlying the G. cancellatum Band; a contorted band 2 or 3 in thick, was also present just beneath the marine band.

The Fernilee No. 1 Borehole [SK 0124 7823] shows the following (abridged) section of the lower part of these beds: (see p. 237 for underlying beds).

Thickness

Depth

feet

inches

feet

inches

Strata uncertain (not cored to 140 ft and cores badly smashed and ?caved below)

167

0

Mudstone, pale silty, with thin siltstone bands

21

0

188

0

Mudstone, with ironstone bands

68

0

256

0

Mudstone, medium to dark grey, with thin ferruginous bands

1

1

257

1

Gastrioceras cumbriense Marine Band

Mudstone, medium to dark grey, with thin ferruginous bands in upper part; lowest 1 ft hard and platy; Lingula enytilloides, Palaeonello ?

11

258

0

Mudstone, dark grey: cf. Angyomphalus sp., Caneyella sp. [juv.], Anthracoceras sp., Gastrioceras crenulatum, G. cumbriense

2

0

260

0

Mudstone, medium to dark grey pyritous; Planolites ophthalmoides 3 in from base

6

9

266

9

Mudstone, grey, with some ironstone bands; Cochlichnus kochi at 274 ft, fucoids' below 283 ft, fish debris from 283 ft 2 in to 284 ft 3 in

18

9

285

6

Gastrioceras cancellatum Marine Band

Mudstone, blocky to 287 ft 2 in, hard dark platy calcareous below; Caneyella sp., Dunbarella sp., Agastrioceras carinatum, Anthracoceras sp., Gastrioceras crencellatum, mollusc spat

1

10

287

4

Mudstone, hard dark platy calcareous; Anthracoceras sp. and mollusc spat at 288 ft to 288 ft 2 in; Gastrioceras cf. crencellatum and mollusc spat at 288 ft 6 in; Gastrioceras cancellatum and Reticuloceras superbilingue at 288 ft 9 in. (see p. 237 for underlying beds)

1

5

288

9

The Fernilee No. 2 Borehole [SK 0119 7863] shows the following (abridged) section of the beds underlying the Rough Rock:

Thickness

Depth

feet

inches

feet

inches

Rough Rock (see p. 245)

303

9

Mudstone, 5-in band with plants at 306 ft 2 in; micaceous below

4

8

308

5

Sandstone, medium- to fine-grained turbulent-bedded

2

0

310

5

Mudstone, with micaceous and silty bands; some plant debris

6

5

316

10

Mudstone, paler above, darker and with some micaceous streaks below; a little pyrite and some plant debris including Mariopteris sp. at 320 ft; cf. Cochlichnus sp. at 323 ft 8 in, 324 ft 9 in and 331 ft 8 in; Naiadites sp. [juv.] at 325 ft 9 in to 331 ft 8 in

15

8

332

6

Siltstone, banded argillaceous

1

2

333

8

Sandstone, banded flaggy

3

8

337

4

Mudstone, banded silty

1

1

338

5

Mudstone, silty, with interbedded siltstone and sandstone

8

11

347

4

Mudstone, dark above, silty micaceous below; plant with attached Spirorbis, cf. Cochlichnus sp., Naiadites sp. [juv.] 347 ft 9 in to 349 ft 1 in

6

6

353

10

Mudstone, silty, with siltstone bands

4

8

358

6

Mudstone, with dark bands and silty in places, with thin siltstones ; some plant debris; thin ironstone bands in places below 367 ft 9 in; cf. Cochlichnus sp. at 371 ft 1 in to 373 ft 8 in; Naiadites sp. [juv.] at 373 ft 7 in

35

6

394

0

Siltstone, banded micaceous, with silty mudstone partings

6

0

400

0

Mudstone, banded silty

13

2

413

2

Mudstone, with ironstone bands and lenses

12

4

425

6

Mudstone, banded silty, with thin siltstone and sandstone bands; cf. Cochlichnus sp. at 436 ft 6 in and 439 ft 2 in

17

3

442

9

Sandstone, fine-grained flaggy

1

11

444

8

Mudstone, banded silty

17

6

462

2

Siltstone, banded

1

10

464

0

Mudstone, thin silty and ferruginous bands; cf. Cochlichnus sp. at 467 ft 7