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Geology of the Stow-on-the-Wold area, 1:10 000 Sheet SP 12 NE. Part of 1:50 000 Sheet 217 (Moreton-in-Marsh) British Geological Survey Technical Report WA/00/12

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M.G. Sumbler

Bibliographic reference: Sumbler, M.G. 2000. Geology of the Stow-on-the-Wold area (SP 12 NE).

©NERC copyright 2000. Keyworth, Nottingham, British Geological Survey 2000

Geographical index: UK, S England, Gloucestershire, Stow-on-the-Wold, Condicote, Longborough, Moreton-in-Marsh

1 Introduction

This report describes the geology of 1:10 000 Geological Sheet SP 12 NE (Stow-on-the Wold), and is best read in conjunction with that map.

Sheet SP 12 NE, herein referred to as the Stow-on-the-Wold area, falls within BGS 1:50 000 Geological Sheet 217 (Moreton-in-Marsh). The first geological survey of the area was undertaken by E Hull during the 1850s; it was published as part of Old Series One-Inch Geological Sheet 44 in 1856, and described by Hull (1857). Hull's survey was used as the basis for New Series One-Inch Geological Sheet 217, published in 1929, which included amendments and additions, notably (for the Stow-on-the-Wold area), the insertion of drift and the Chipping Norton Limestone by H G Dines, the latter based on notes by L. Richardson (six-inch maps Gloucs 21NE, 21SE, 22NW, 22 SW). The geology of Sheet 217 was described in a memoir by Richardson (1929) based on the work of Hull, supplemented by additional data such as quarry sections recorded mainly by Richardson himself, and by Dines' drift survey (Dines in Richardson, 1929). Sheet 217 was reissued at 1:50 000 scale in 1975, and reprinted with additional amendments and revised marginal information in 1981.

The whole of the Stow-on-the-Wold area (SP 12 NE) was surveyed at the 1:10 000-scale by M G Sumbler during October 1996 and May 1997, as part of the resurvey of Sheet 217, which was completed in June, 1998. A new edition of Sheet 217 will be published during 2000. In addition to data acquired on the ground, use was made of earlier geological maps, records of boreholes and wells, and commercially available aerial photography. The resulting map includes some important revisions to the earlier maps, perhaps most importantly with regard to the classification and distribution of units within the Inferior Oolite and Great Oolite groups, and the recognition of the extent of cambering phenomena. This report is based mainly on this latest work, but also incorporates data from other sources where appropriate, as indicated herein (see References and Unpublished Information Sources). Measured sections from the lettered localities indicated on the map and referred to in the text are given in Appendix 1.

The Stow-on-the-Wold area straddles an eastern promontory of the Cotswold Hills, made up of Middle Jurassic limestone strata of the Inferior Oolite and Great Oolite groups, with the land reaching an elevation of just over 235 m above OD (Ordnance Datum) in several places. The low-lying Vale of Moreton (part of the Evenlode valley), excavated into mudstones of the Lower Jurassic Lias Group, enters the north-eastern part of the area, and the north-south valley of the River Dikler transects the middle part.

The large village of Stow-on-the-Wold, a popular tourist venue, is located on some of the highest ground in the south-eastern part of the area, at an important road junction on the Foss Way, the Roman road from Cirencester to Lincoln. Several other small villages occur in the area. Longborough and Donnington overlook the Vale of Moreton in the north-east; Upper and Lower Swell have sheltered locations in the Dikler valley and Condicote lies in the northwest. Outside the villages, the area is mainly given over to farming, with the high ground used for arable, whilst the steeper slopes and valleys are mainly pastureland used for sheep and dairy cattle.

Notes:

Both this report and the corresponding map (Geological Sheet SP 12 NE) should be regarded as interim or preliminary documents pending publication of a full account of Sheet 217; in particular, certain geological concepts and lithostratigraphical names may be subject to future revision. The map indicates the outcrop limits of deposits which are mostly concealed beneath soil and vegetation; the geological boundary lines are inferred from indirect evidence such as the form of the ground surface and soil type, or are extrapolated from adjoining ground. The map is thus the subjective interpretation of the surveyor, and all geological boundaries carry an element of uncertainty. Boundaries of solid geological formations which, in the opinion of the surveyor, can be located to an accuracy of about 10 m or better on the ground, are shown as unbroken lines; all others are shown broken.

Copies of the 1:10 000 map can be purchased from BGS, Keyworth, where records of boreholes and other data may also be consulted by prior arrangement. Copyright restrictions apply to the use of both the map and this report, and to the copying of the material thereof. The map and report are internal publications of the BGS and any information extracted from them should be acknowledged by the appropriate bibliographical reference.

Equivalent technical reports covering adjoining sheets to the North West, East and South are as follows:

SP 13 SE (Bourton-on-the-Hill) WA/99/27 (Sumbler, 1999c)

SP 22 NW (Oddington) WA/99/15 (Sumbler, 1999b)

SP 12 SE (Bourton-on-the-Water) WA/99/07 (Sumbler, 1999a)

SP 12 NW (Chalk Hill) WA/99/41 (Sumbler, 2000).

Throughout this report National Grid References are given in square brackets; all lie within 100 km grid square SP (or 42) unless otherwise stated.

(Table 1) Geological sequence proved within sheet SP 12 NE (Stow on the Wold)

2 Lower Jurassic: Lias Group

The mainly mudstone succession of the Lias has traditionally been divided into Lower, Middle and Upper Lias. These ill-defined units are now replaced by lithostratigraphical formations, as described by Cox, Sumbler and Ivimey-Cook (1999).

2.1 Charmouth Mudstone Formation

The Charmouth Mudstone, corresponding with the 'Lower Lias clays' etc. of previous accounts, is the oldest formation present at outcrop in the Stow-on-the-Wold area, occurring to the east of Longborough in the north-east corner. An estimated 15 m or so of strata, representing the topmost beds of the formation, are represented at the surface. The total thickness of the formation is uncertain but, given the structural situation of the area, straddling the margin of the Worcester Basin (see Structure), it is likely that the formation thickens somewhat in a westward or north-westward direction across the Stow-on-the-Wold area (see Horton et al., 1987, fig. 15; Sumbler, 1998a, fig. 1), perhaps within the range c. 160 to 200 m. The underlying Blue Lias Formation, the basal unit of the Lias Group, again thickens to the west or north-west, probably within the range of approximately 30 to 40 m.

The beds of the Charmouth Mudstone Formation at outcrop produce a brownish grey silty clay soil. Debris from a trench alongside the Fosse Way comprised pale bluish grey, fawn-weathering clay with sporadic sideritic ironstone nodules; the latter break down to form chips of black or ochreous brown limonite in the soil. Immediately north of Little Barrow Bridge, [SP 199 293] debris of hard, bluish grey shelly limestone associated with grey to yellow smooth-textured limestone nodules may represent the so-called 100 Marker, known from geophysical borehole logs in the region and believed to lie approximately 10 m below the top of the formation (Horton and Poole, 1977; Horton et al., 1987; Sumbler, 1998a).

2.2 Dyrham Formation

The Dyrham Formation approximates to the 'Middle Lias silts and clays' of some accounts, or the 'Sandy Beds' of Richardson (1929). It crops out on the lower slopes of the escarpment in the north-east, and also on the eastern side of the Dikler valley, to the west and south-west of Stow. Where fresh (at depth) the formation comprises pale grey to brown silts and silty mudstones, with some beds of fine-grained sandstone. At the surface, however, the outcrop is characterised by a reddish brown silty clay soil, and pinkish grey or ochreous silty clay is seen in ditches. Rarely, chips of sandstone or limonite (weathered sideritic nodules) may occur in the soil. The base of the formation (seen only in the north-east) is mapped at the break of slope at the foot of the scarp, and is commonly marked by weak groundwater seepage. The formation is approximately 20 m thick in the north-east; apparently smaller thicknesses seen locally are probably due to cambering of the succeeding Marlstone Rock. It is likely that it thickens somewhat across the Stow-on-the-Wold area, perhaps within the range 20 to 30 m, though it may be a little thicker at depth in the west and north-west.

2.3 Marlstone Rock Formation

The Marlstone Rock Formation, lying between the Dyrham Formation and Whitby Mudstone, forms a prominent shelf along the scarp slope to the south-east of Longborough, i.e. between The Gorse [SP 179 284] and Pens Coppice [SP 195 287] where it gives rise to a reddish brown loamy soil containing chips of brown sandstone and shelly ironstone. These rocks contain a proportion of limonitic ooids (probably altered berthierine). Immediately west of Pens Coppice, it forms a broad, well-developed dip slope. It is estimated to be approximately 3 m thick hereabouts. Elsewhere, the outcrop is very hard to locate and in many places its mapped outcrop is essentially conjectural. It is quite likely that this is due to its local absence as known in some other areas on the margin of the Worcester Basin (see Sumbler et al., 2000) but equally may be a result of obscuration by material from the overlying Whitby Mudstone. For example, in Abbotswood Park, in the Dikler Valley, an exposure (Locality X [SP 1861 2603]) showed 1.5 m of Marlstone Rock (grey to rust-brown sandy and finely ooidal limonitised ironstone) in a part of the area where there is otherwise no other indication of the presence of the formation.

2.4 Whitby Mudstone Formation

The Whitby Mudstone Formation (the Upper Lias of previous accounts) forms the upper slopes of the scarp in the north-east, and also occurs along the Dikler valley, and minor valleys on the eastern margins of the area. The thickness of the formation remains uncertain. As measured from contour intercepts, it appears to average about 25 m (as stated on the 1:10 000 map), though locally it appears to be substantially less as a result of cambering of the overlying strata of the Inferior Oolite Group. In fact it is possible that even the 25 m figure is an underestimate; in common with the regional pattern in the rest of the Lias, one would expect the formation to thicken towards the west or north-west and, on the basis of data from adjoining areas, a range of perhaps 35 to 50 m or more seems plausible (see Sumbler, 1999a; c). Nevertheless, it remains possible that there is some localised thinning in this area, caused by overstep of the youngest beds by the Middle Jurassic Inferior Oolite Group on the margin of the Worcester Basin (see below and Structure).

The outcrop of the Whitby Mudstone is characterised by grey to fawn, slightly silty clay soils. Exposures in other areas show that when fresh it comprises bluish grey, commonly rather fissile, finely micaceous mudstones with small calcareous nodules and silt lenticles at some levels. Material of this type was proved by excavations at Lower Swell [SP 1754 2556] and [SP 1772 2560]. At the top of the formation, a thin unit of yellowish buff, fine-grained and slightly micaceous clayey sand that succeeds the grey mudstones has been just beyond the northwestern and south-western corners of the area ([SP 1449 2437] and [SP 1501 3061]; Barron, 1999; Sumbler, 2000). This unit representing the feather-edge of the Upper Toarcian Bridport Sand Formation (formerly Cotteswold Sands), is probably present at depth in the west of the Stow-on-the-Wold area, but does not appear to be present where the Whitby Mudstone crops out, probably having been cut out beneath the downcutting base of the Inferior Oolite Group. Evidence of this is provided by Richardson's (1926, p. 69; 1929, p. 31) record of 'clay' with Dactylioceras and Porpoceras, suggesting the Lower Toarcian Bifrons Zone, from the foundations of Duncombe House [SP 177 279] which is sited very close to the local top of the formation.

3 Middle Jurassic: Inferior Oolite Group

Middle Jurassic strata, mainly limestones, crop out over most of the Stow-on-the-Wold area. The Inferior Oolite Group constitutes the lower part of this succession, cropping out on the slopes of the valleys and more extensively in the northern and south-eastern parts of the area. The group is divisible into three formations, the Birdlip Limestone, Aston Limestone and Salperton Limestone, in ascending order (Barron et al., 1997), corresponding with the traditional subdivisions of Lower, Middle and Upper Inferior Oolite respectively. Based mainly on information from adjoining areas (Sumbler, 1999c, d) it seems likely that the Inferior Oolite Group is at least 45 m thick in the west, and possibly up to c. 70 m in the north-west corner, but thins to 10m or (locally) less in the east, due to the progressive eastward overstep of the Birdlip Limestone by the Salperton Limestone across the Vale of Moreton Axis (see Barron et al., 1997).

3.1 Birdlip Limestone Formation

Because of the effects of cambering, it is not possible to gauge the thickness of the Birdlip Limestone with any accuracy, but it is about 30 m thick in the Eye valley immediately beyond the south-west corner of the area (Sumbler, 2000) and may be 50 m or more in the north-west corner (see Sumbler, 1999c). There, the Birdlip Limestone is made up of four members, the Leckhampton Member, Cleeve Cloud Member, Scottsquar Member and Harford Member in ascending order. The formation would appear to be only 5 to 10 m thick in the eastern half of the area, where only the Leckhampton Member and the lower part of the Cleeve Cloud Member are present. It thins to zero in the south-east where overstepped by the Salperton Limestone.

3.1.1 Leckhampton Member

The Leckhampton Member (formerly Scissum Beds), the basal unit of the Inferior Oolite Group, is probably up to about 5 m in thickness, but is commonly less, 2 to 3 m being typical. It comprises grey to orange brown, ferruginous, typically rather rubbly very sandy limestone or calcareous sandstone, generally with a proportion of very fine-grained ooids and shell fragments. At outcrop, it is generally more or less decalcified to a yellowish to reddish brown sand or loam. Whilst it is believed to be present at the base of the Birdlip Limestone throughout the area, in some places it can be difficult to separate from the overlying Cleeve Cloud Member which likewise has a tendency to decalcify to loam. In such places, it is not separately distinguished on the map.

3.1.2 Cleeve Cloud Member

The Cleeve Cloud Member in this area corresponds with the Lower Freestone of Richardson (1929) to parts of which he applied the terms 'Yellow Stone', 'Pea Grit Series' or 'Pea Grit Equivalent' in various accounts. It may locally be over 40 m thick in the west, but over most of the area 5 to 15 m is probably typical, it being particularly thin in the east. It is dominated by white to yellowish brown, fine to medium-grained, generally well-sorted and flaggy (cross-bedded) ooidal grainstone, commonly sandy and ferruginous, in some cases with veins of brown secondary limonite. The limestones are particularly yellowish and ferruginous in the east (Richardson's 'Yellow Stone'). The ooids typically comprise rather pale carbonate coatings around darker quartz sand-grain nuclei, and because of this sand content, the limestones weather to produce a loamy soil much like that characterising the Leckhampton Member, though generally a certain amount of yellowish brown, flaggy oolite brash is present.

The top surface of the Cleeve Cloud Member where succeeded by the Scottsquar Member in the west is commonly developed as a bored and locally oyster-encrusted hardground (see e.g. Locality L [SP 1630 2993]. Farther east, where Salperton Limestone rests directly on the Cleeve Cloud Member, the top of the Cleeve Cloud Member is commonly re-cemented but no borings or epifauna have been observed (see for example Locality P [SP 1733 2770]), although they have been noted at this horizon in some adjoining areas. The best exposure of the Cleeve Cloud Member in the Stow-on-the-Wold area is at Longborough Quarry (Locality N [SP 171 295] where some 6 m of cross-bedded oolite is exposed. Woodward (1894) reported a ‘pisolitic’ band in the section there, but this has not been observed by the present author; indeed coarse grained beds are very rare. At a site believed to be Lower Swell Quarry (Locality Q [SP 1677 2517]) Richardson (1904; 1907; 1929) recorded 'a remarkable deposit...almost wholly made up of the valves of oysters...'. Given the location of the site, this would seem to be an unusual facies within the Cleeve Cloud Member.

3.1.3 Scottsquar Member

The Scottsquar Member corresponds with the Upper Freestone and Oolite Marl of previous accounts. Partly based on information from adjoining areas, it is estimated to be up to about 8 m in thickness. It is present only in the western part of the area, being cut out (overstepped) by the Salperton Limestone in the east. The most easterly occurrences of the Scottsquar Member, and of the Harford Member, occur in faulted outcrops in the neighbourhood of Lower Swell. There they occur some 1 to 2 km farther east than they do immediately to the south (Sheet SP 12 SE; Sumbler, 1999a) providing circumstantial evidence that contemporaneous trough-faulting may have been a factor assisting the local preservation of these units beneath the Salperton Limestone. Unusually, near Hans Hill Farm [SP 165 298] the eastern limit of the Scottsquar Member apparently occurs where it is cut out by the succeeding Harford Member. Similar relationships occur to the north (Sumbler, 1999c), although whether they result from channelling at the base of the Harford Member or lateral passage of the Scottsquar Member into Harford Member facies is uncertain. The former is quite probable; the presence of an oyster encrusted hardground at the top of the Scottsquar Member where succeeded by the Harford Member e.g. [SP 163 251] indicates a disconformable relationship between the two in this area.

The Scottsquar Member is dominated by white to pale brownish lime mudstone (micrite) and sparsely peloidal wackestones. This is the facies of the `Oolite Marl' although unusually, the strata are generally poorly fossiliferous in this area. Less commonly, white to pale grey medium to coarse-grained peloid and ooid packstone to grainstone occurs Clipper Freestone' facies). The succession probably includes marly or clayey interbeds as the soils on the outcrop are typically dark brown clays with more or less limestone brash.

The Scottsquar Member was formerly exposed in Sezincote Hill Quarry (Locality L [SP 1630 2993]) where Richardson (1929) recorded c. 1.1 m of marl and rubbly limestone with brachiopods.

3.1.4 Harford Member

The Harford Member, the youngest member of the Birdlip Limestone, is preserved locally in the west. It is estimated that up to about 5 m of strata are represented. In the south-west the strata are dominated by yellow to brown sandy fine to medium grained oolites, not unlike some beds in the Cleeve Cloud Member. Near Hans Hill Farm on the northern margin of the map, soils suggest that the beds are dominated by reddish brown sands and sandy clays with some beds of calcareous sandstone. In a trench there (Locality M [SP 162 300]), Richardson (1929) noted c. 2.3 m of sandy clay and marl with a bed of yellow limestone.

3.2 Aston Limestone Formation

The Aston Limestone Formation is not present at outcrop in the Stow-on-the-Wold area, due to overstep by the Salperton Limestone. However, it is possible that its feather edge may occur at depth in the north-western corner, as it is known to be present immediately to the north and west (Sumbler, 1999c; d).

3.3 Salperton Limestone Formation

The Salperton Limestone Formation, the youngest unit of the Inferior Oolite Group in the Cotswolds, has an extensive outcrop in the Stow-on-the-Wold area. Only the Clypeus Grit Member is represented; there is no evidence of the Upper Trigonia Grit which is present at the base of the formation farther west. The Clypeus Grit is typically a yellowish brown to white, very coarse-grained ooid and shell fragment packstone, characteristically containing large ovoid peloids and grain aggregates, and producing a rubbly brash in arable fields. The beds are commonly quite fossiliferous, with brachiopods (notably Stiphrothyris), myid bivalves and the large echinoid Clypeus ploti Salter. The last is particularly common in the upper beds of the member. Ammonites are also relatively common in the Clypeus Grit; a segment of a parkinsoniid in a matrix of typical Clypeus Grit was found in brash on the Harford Member outcrop near Hans Hill Farm [SP 1634 2998].

Because of extensive cambering, the thickness of the formation is somewhat uncertain, but a range of from 5 to 10 m seems probable, with the minimum probably occurring in the east of the area. The upper part of the formation is exposed in the Fosse Way road cutting north of Stow-on-the-Wold (Locality U [SP 194 272]) and also near Donnington Brewery (Locality P [SP 1733 2770]). The basal beds were formerly exposed at Triangle Quarry (Locality V [SP 1946 2743]).

4 Middle Jurassic: Great Oolite Group

About 40 m of strata, representing nearly the whole of the Great Oolite Group, crop out in the Stow-on-the-Wold area. The entire group is some 45 to 50 m in thickness in the area to the west (Sumbler, 2000), considerably less than the 80 to 85 m or so for the equivalent strata in the Cirencester district to the south (Sumbler et al., 2000). It seems likely that this part of the north Cotswolds was an area of reduced subsidence during deposition of the Great Oolite Group (Bathonian) and, judging from some of the facies of the sediments, probably an area of particularly shallow water for much of this period. Most of the component formations are thin, but the succession is largely complete, and there is little evidence of eastward thinning and overstep as is the case in the Inferior Oolite Group. It would seem, therefore, that the Vale of Moreton Axis had stabilised by the Bathonian (see Sumbler, 1999d).

4.1 Chipping Norton Limestone Formation

The Chipping Norton Limestone, the basal unit of the Great Oolite Group, is the most extensive formation in terms of its area of outcrop, occupying much of the higher ground of the area. Its thickness is somewhat difficult to judge because of cambering and other structural complications, but it is estimated to be within the range of about 9 to 15 m.

The formation was formerly worked at many sites (see Appendix 1; localities A, B, C, D, E, F, I, O R, S, T, U, W) and the records of the sections give a good impression of the various lithologies that occur. The greater part of the formation is composed of pale brown to buff or grey, more or less shell-fragmental ooidal grainstone. It is generally medium-grained and slightly sandy, but coarser, shell-fragmental limestones occur in places. Typically it is cross-bedded and flaggy or platy weathering, but more uniform or rubbly-weathering beds also occur. The basal beds of the formation tend to be particularly sandy and argillaceous producing a brownish grey platy brash, commonly intensely burrowed. Oyster-rich limestones and marls tend to be associated with these beds. Hard, fine grained thinly bedded limestones tend to occur in the upper part of the formation and have been worked for roofing tilestones in a few places, notably at Poles Plantation (Locality C [SP 1692 2654]). These beds include lithologies rather similar to those found in the Eyford Member (Fuller's Earth Formation) that is developed above the Chipping Norton Limestone to the west, and may conceivably include lateral equivalents (see below and Sumbler, 2000).

A rather unusual facies of the Chipping Norton Limestone occurs locally, particularly in the neighbourhood of Donnington covered reservoir [SP 1919 2759]. It comprises a pale grey to white sparsely peloidal wackestone strongly resembling lithologies of the Scottsquar Member and White Limestone Formation. In 1998, a 3 m deep excavation [SP 1922 2753] showed that this material occurs as lenses and pebbles in a marly limestone, which was associated (interbedded) with more characteristic lithologies of the Chipping Norton Limestone, comprising soft, sandy fine-grained oolite and marly clay with oysters. Minor quantities of similar micritic limestones were found in brash in the vicinity of Banks Fee Farm and Greenfield Farm [SP 167 284; 184 266], and pebbles of 'whitish lithographic stone' were recorded from a bed in Fenwick's Quarry (Locality B [SP 1642 2639]) by Richardson (1929). In all cases, these limestones are believed to occur fairly close to the base of the formation.

Other than oysters (Praeexogyra; see above) recognisable macrofossils are not common in the Chipping Norton Limestone but mention should be made of the ammonite Oppelia obtained from near Standles Coppice [SP 169 256], and Parkinsonia from New Park Quarry (Locality O [SP 1744 2816]). Both specimens came from horizons low in the succession and are consistent with the Lower Bathonian Zigzag Zone (Arkell and Donovan, 1952; Torrens, 1969). Also important are reptile remains particularly those from New Park Quarry SSSI which has yielded a substantial quantity of material partly as a result of investigations for the British Association in the 1930s (Reynolds, 1939; Benton and Spencer, 1995). Specimens include bones of crocodiles (Steneosaurus, Teleosaurus), as well as terrestrial forms such as theropods (Megalosaurus), sauropods (Cetiosaurus) and stegosaurs (Lexovisaurus). The latter imply the proximity of land as also indicated by a vertebrate fauna associated with a palaeokarst surface in the Chipping Norton Limestone at Hornsleasow [SP 131 323], 6 km to the north-west of New Park Quarry (Metcalf et al., 1992).

4.2 Fuller's Earth Formation

The Fuller's Earth Formation comprises two parts, a basal, un-named unit of mudstones and an upper unit of limestone and sandstone known as the Eyford Member. The formation is poorly developed in the Stow-on-the-Wold area, being present only locally in the west where it is from zero up to about 4 m in thickness. This meagre development compares with thicknesses of up to about 10 m in the area immediately to the west where the Eyford Member is particularly well developed (Sumbler, 2000), and appears to be a localized phenomenon related to the Vale of Moreton Axis. It is believed to result mainly from eastward (or north-eastward) facies passage into strata classified as Chipping Norton Limestone (Sumbler, 2000) but may in part be caused by erosional downcutting of the succeeding Taynton Limestone (as has been suggested by Wyatt, 1996).

The basal mudstone unit of the Fuller's Earth has been recognised only at one locality [SP 158 294] in the north-west of the area, where an outcrop of dark brown clayey loam with pieces of grey thinly fissile sandy limestone (tilestone) has been mapped between the Chipping Norton Limestone and Taynton Limestone. It seems unlikely that the mudstone unit is more than 2 m thick hereabouts and could be less. There is no indication of the Eyford Member at this locality, whilst c. 900m to the south-east [SP 163 286], the mudstones are apparently absent, but c. 2 to 4 m of Eyford Member, comprising hard, grey planar-bedded fissile sandy limestone (tilestone) is present. Thin Eyford Member is also present on the western margin of the map [SP 150 272].

4.3 Taynton Limestone Formation

Several outcrops of Taynton Limestone occur around Condicote in the north-west of the area, where it rests variously on Fuller's Earth or directly on Chipping Norton Limestone. As discussed above, this may in part result from an erosive, overstepping relationship with the underlying strata. The formation is estimated to range from about 3 to 5 m in thickness, less than half that general in its type area near Burford, some 15 km to the south-east (Sumbler et al., 2000). It is dominated by white to pale buff, medium to coarse-grained, generally well sorted ooid and shell fragment grainstone that is generally rather poorly cemented and forms a brash of rather small, crumbly fragments in the fields, in marked contrast to the greyish brown, flaggy or tiley brash of the underlying Eyford Member or Chipping Norton

Limestone. The best current exposure of the formation is at Luckley Farm Quarry (Locality J [SP 1609 2882]) which exhibits the typical cross-bedded oolites with marl bands. It was previously exposed in Condicote Quarry (Locality H [SP 1540 2823]), and is also poorly exposed in a downfaulted outcrop at Guiting Road Cutting (Locality G [SP 1665 2724])where it appears to be only c. 2.5 m thick.

4.4 Hampen Formation

The Hampen Formation overlies the Taynton Limestone in the north-west, where it is estimated to be c. 3 to 5 m in thickness; this compares with some 9 m at the type section, some 8 km to the south-west (Sumbler and Barron, 1996). The strata comprise brown to fawn-weathering marls and clays, commonly containing lenticles of sandy limestone and fine-grained oolite, as well as thicker beds thereof, which include thinly bedded fissile `tilestonee, as well as blocky and structureless, probably intensely burrowed beds. The basal c. 1 m of the formation, mainly marls, is exposed at both Locality J [SP 1609 2882] and Locality G [SP 1665 2724].

4.5 White Limestone Formation

The White Limestone Formation crops out on the western margins of the area near Condicote, in a narrow graben extending south-eastwards to Flagstone Farm [SP 161 276], and also around Luckley Farm [SP 162 289]. The total thickness of the formation, preserved only near Flagstone Farm, is probably about 15 m as in the area to the west (Sumbler, 2000). This is somewhat thinner than farther south in the Cotswolds (Sumbler et al, 2000), although in this area it appears that only the Shipton and Ardley members are present; the topmost unit (the Signet or Bladon Member) being absent, probably due to erosive overstep by the Forest Marble.

Judging from field brash, the formation is made up largely of white to pale grey more or less peloidal wackestones with subordinate peloidal packstone. More rarely, grainstones occur, as indicated by an exposure at Luckley Farm (Locality K [SP 1616 2889]). Beds of marl and clay are also present as indicated by excavations at Cotswold Farm, Condicote [SP 152 282] which revealed fawn and grey clays with sporadic Praeexogyra hebridica. The White Limestone is generally rather sparsely fossiliferous, although nerineid gastropods are abundant locally, as are brachiopods (mainly Epithyris). Near Luckley Farm common echinoids (Nucleolites and Clypeus mulleri) have been found near the base of the formation [SP 163 288] and [SP 168 291]. Other fauna from the White Limestone of this area is recorded by Welch (1927, and in Richardson, 1929, p.119).

4.6 Forest Marble Formation

A small outlier of Forest Marble is preserved above White Limestone in a graben at Flagstone Farm [SP 161 276]. The soils on the outcrop comprise brown clays containing brash of fairly flaggy brown to blue shell-fragmental ooidal limestone and oyster-rich limestone. It is estimated that up to about 4 m of strata are represented, which may be close to the full thickness of the formation hereabouts as proved in the area to the west, where it is about 6 m thick (Sumbler, 2000).

5 Structure

5.1 Diastrophic structures

The phenomenon of eastward thinning of the Jurassic succession across the region (as discussed above) has been ascribed to a so-called Vale of Moreton Axis, often regarded as a symmetrical axis of uplift. This is better regarded as a 'hinge' rather than an 'axis' (Sumbler et al., 2000), and corresponds to the margin of the Worcester Basin in the west against the London Platform in the east. The Worcester Basin was an area of subsidence during Triassic and Early Jurassic times, and thick successions of sediment accumulated within it, as revealed by boreholes and seismic data in this and adjoining areas. By contrast, the London Platform, a massif of Palaeozoic rocks, remained stable throughout the Mesozoic Era and, as a result, is covered by a relatively thin Mesozoic sedimentary sequence. For example, in the Guiting Power Borehole [SP 0855 2450] (Barron, 1998), sited within the Worcester Basin some 6 km to the south-west of the Stow-on-the-Wold area, the Permian and Mesozoic succession is some 2 km thick. By contrast, in the eastern part of the Stow-on-the-Wold area it is estimated to be less than one quarter of this thickness. Seismic data (interpreted by T C Pharaoh, BGS) indicate that much of the thinning takes place in a relatively narrow zone (i.e. the edge of the Basin) which, in the Stow-on-the-Wold area, crosses the area from north to south close to or a little to the west of the Dikler Valley. Within this zone, faults at depth can be discerned on the seismic traces. Their throw diminishes up-sequence indicating that they were probably active during sedimentation (growth faults). Details at shallower depth is not clearly resolved on the seismic traces, so it remains unclear to what degree the faulting affects the Lias and whether or not it continues to the surface.

Overall, the structure seen within the Middle Jurassic strata at the surface reflects the structure at depth, with a weak westward-facing monocline developed over the basin margin. This is most clearly appreciated after making allowance for the general south-eastward regional dip of the Jurassic strata. In more detail, the tectonic structure is difficult to disentangle from the superficial structures (see below). A fault within the Lias following the Dikler Valley is inferred from surface mapping. Near Lower Swell this may have a westward down-throw of over 50 m but there are considerable uncertainties introduced by superficial structures and relations could equally well involve a more or less sharp monocline there. Where the extension of this inferred fault crosses the Inferior Oolite Group and Great Oolite Group outcrop near New Park Quarry [SP 176 282] its throw is very small (< 5 m), suggesting that, as in the Trias, this could be a growth-fault, that stabilised before deposition of the Inferior Oolite. This could help explain the apparent loss of the upper part of the Whitby Mudstone succession in the eastern part of the area (see above). Seismic data from deeper levels would suggest that this fault extends northwards through the area, but there is no surface expression of such a fault, which might be expected to reach outcrop within the tract of Inferior Oolite to the west of Longborough. It remains possible that there may be a fault within the Lias thereabouts, but that it does not affect the Inferior Oolite cover. North to south and north-west to south-east trending faults mapped at the surface close to the western margin of the area can again be related to basin boundary faults at depth on seismic sections, but these do affect the Inferior Oolite Group and Great Oolite Group cover, with westward throws probably exceeding 20 m in places.

Faults trending predominantly west-north-west to east-south-east are common in the Stow-on-the-Wold area, and particularly so in the south-west where they form a belt of faults that dissect the Inferior Oolite outcrop into narrow, alternating graben and horst. Although this fault belt trends approximately at right angles to the margin of the Worcester Basin, and is presumably unrelated to it, there is a possibility that they may have had some effect on Inferior Oolite Group sedimentation as, within the fault belt, the locus of overstep of the Harford and Scottsquar members lies over a kilometre farther east than it does to its north or south.

5.2 Superficial structures

The category of superficial (non-diastrophic) structures encompasses cambering and valley bulging, which are folding, faulting and displacement phenomena that are related essentially to the topography of the land surface. They are particularly significant in the Stow-on-the-Wold area, as in the Cotswolds in general, and in many cases may be on a larger scale than diastrophic structures. Within the present area, both cambering and valley bulging are caused fundamentally by the deformation and consequent movement of the clays of the Whitby Mudstone Formation near outcrop, where these are subject to the load of overlying strata. This may lead to the collapse or deformation of overlying more competent strata of the Inferior Oolite and Great Oolite groups. These effects probably took place under a periglacial regime during the cold 'glacial' phases of the Quaternary Period.

Cambering is particularly severe for up to a kilometre on either side of the Dikler valley downstream of the Donnington Brewery, and on the margin of the Eye valley in the southwest corner of the area, so that overall, the outcrops dip down towards the axes of the valleys, obscuring the true tectonic structure. Major gulls occur, as originally described by Briggs and Courtney (1972) who, dealing chiefly with the area immediately to the south (Barron, 1999; Sumbler, 1999a), coined the apt term 'ridge and trough topography.' The principal gulls, which are indicated on the map, typically take the form of linear, flat-bottomed troughs, generally more or less parallel to the hill contours. In extreme cases (e.g. in Long Plantation [SP 154 253]), these gulls may be 5 m or more in depth, and several hundred metres in length, and appear much like artificial cuttings. From data elsewhere (Barron, 1999), it seems probable that these trough-like gulls are actually small graben formed between minor sub-parallel faults, which result from slight extension of the competent limestone strata consequent on lateral and downhill movement on the incompetent Whitby Mudstone substrate. Other 'gulls' take the form of linear steps in the hill slope; these may have formed on single, perhaps rotational faults. In many cases these superficial faults affect the outcrop pattern of various formations, giving rise to marked offsets or outliers e.g. [SP 173 266]. In a few cases, probable tectonic faults have been re-activated by cambering, coinciding with gulls e.g. [SP 169 255]. The large gulls marked on the map generally occur on the uppermost valley slopes; the lower slopes are generally smooth and almost planar as typified by the Inferior Oolite Group outcrops around Lower Swell, to both the west and east of Stow, and on the margin of the Vale of Moreton west of Longborough. Though giving the appearance of dip-slopes, these planar slopes are believed to be cambered, being made up of multiple faulted and rotated blocks (Sumbler, 1999a; 1999c).

Valley bulging probably affects the Whitby Mudstone in the valley floors but in the absence of good exposures, this is difficult to prove. Evidence of valley bulging is better authenticated in adjoining areas as discussed in the appropriate reports (Sumbler, 1999a; 1999c).

6 Quaternary

6.1 Till

A small (c. 0.25 ha) area of till occurs on the north-eastern margin of the area. This is part of an extensive spread of glacial deposits that occur in the Vale of Moreton to the north-east and east, more fully described by Sumbler (1998b; in press). Within the Stow-on-the-Wold area, this material is a reddish brown clay with scattered pebbles, mainly quartz and quartzite. This forms part of the Moreton Member of the Wolston Formation.

6.2 Alluvium

A tract of alluvium 50 to 150 m across forms the floodplain of the River Dikler which transects the area. Soils on the floodplain are typically brown silty clays and silts, with pale greyish tufaceous clays in places. At some localities, locally-derived, waterworn, limestone gravel occurs in the soil; this probably forms a more or less continuous layer beneath the alluvial clays. Records of piling bores at Upper Swell Pumping Station [SP 175 270] indicate that the deposits may be up to 2.1 m thick.

An area of clayey alluvium in the north-east [SP 186 296] is the floodplain of a minor stream tributary to the River Evenlode in the Vale of Moreton.

6.3 Head

Many of the dry valleys 'tributary' to the Dikler are floored by reddish brown silty and stony clay. Such deposits probably include ancient alluvium, together with solifluctate and hillwash (colluvium) from the valley sides. The alluvial component must date from periods when streams flowed in the valleys, either during periods of high rainfall, or when permafrost rendered the ground impermeable. Some of the valleys are well known to carry streams during exceptionally heavy rain (e.g. that entering Lower Swell from the north-west). These head deposits are unlikely to exceed 2 to 3 m in thickness.

6.4 Landslip

Substantial landslips affect the Whitby Mudstone Formation and, to a lesser extent, the Dyrham Formation to the north-west of Donnington, at Longborough, and in steep-sided valleys both to the north-west and north-east of Stow-on-the-Wold village. The landslipped ground has been mapped on the basis of its characteristic hummocky topography with poorly drained hollows. Typically, the upper part of the slopes appear to be affected by multiple, small-scale rotational slips, and the lower parts by mass flows. Elsewhere, such features may be partly obscured by agricultural improvements, and it is possible that landslips have gone unrecognised in some areas, notably on the steep slopes in the north-east.

6.5 Artificial deposits and worked ground

In general, the more extensive quarried areas are shown as Worked Ground, and indicated by a hachure ornament. A few of the smaller pits and quarries, mostly more or less infilled and ploughed over, are indicated by a toothed 'cutting' symbol on the map. Very little Made Ground has been mapped as such, but in all cases, the quarries include areas backfilled with quarry waste and perhaps other materials, and it is possible that other quarries, now completely infilled, have gone unrecognised.

7 Economic geology

The Cleeve Cloud Member was worked for building stone in the ancient Longborough Quarry (Locality N) which probably yielded sawn freestone. Most of the other quarries in the area (Appendix 1) worked the Chipping Norton Limestone which was used for walling stone, lime burning and, to a lesser extent, tilestones and flagstones. Flagstones were worked from underground mines near Flagstone Farm (Locality F) according to Richardson (1929). A few quarries worked the Taynton Limestone. This is presumed to have been used mainly for lime burning as the stone seems to be insufficiently durable for building, in marked contrast to the situation in its type area, where it yielded high quality freestones.

A small 'gravel pit' at Waterhead Barn [SP 166 279] marked on old editions of the Ordnance Survey 1:10 560 sheets, probably worked alluvial gravels.

Stream or spring water was formerly the only source of potable water in the area; some details are given by Richardson (1930) who deals particularly with the wells at Stow-on-the-Wold village. Spring water from the Inferior Oolite Group feeds the River Dikler, the permanent head of which, at Waterhead Barn [SP 166 279], probably marks the up-valley-limit of the Lias outcrop, there concealed beneath alluvium. Water from the Dikler is still utilised for public supply at the Upper Swell Pumping Station [SP 1600 2752].

8 Unpublished information sources

The following lists the principal items of unpublished data that were consulted and considered in connection with the survey of Sheet SP 12 NE. All this data is held in BGS archives, and in most cases may be consulted on application to BGS. Published data pertinent to the area is referred to in the text and listed in References.

8.1 Boreholes

As of the date of this report, BGS held records of boreholes/water wells/trial pits and springs for 17 sites within Sheet SP 12 NE. These records are held in the National Geological Records Centre at BGS Keyworth; the geological data vary greatly in terms of quality and reliability. Each borehole is given a unique registration number, in which the borehole logs for each 1:10 000 sheet are numbered consecutively in order of acquisition; thus the full designation is in the form SP 12 NE/1. Sites of the more significant boreholes are indicated on the map.

8.2 Maps

The following large-scale geological maps cover all or part of Sheet SP 12 NE; these unpublished maps are held in the National Geological Records Centre at BGS Keyworth. Those by H G Dines, based on a reconnaissance survey of the Drift, and a 'desk study' to insert the Chipping Norton Limestone Formation and 'Great Oolite' are incorporated within the small-scale published 1:63 360 and 1:50 000-scale Sheet 217 (Moreton-in-Marsh). Some carry brief notes giving details of exposures etc. Those by F B A Welch and L Richardson, dating from the 1920s, are little more than incomplete sketch-maps but carry some notes by Richardson; they form the basis of a paper by Welch (1927). Their maps appear to be items originally used by W. Whitaker, and also include a few notes by him (r) c. 1904) relating chiefly to springs and water supplies. Richardson and Welch's work was not officially sanctioned by the Geological Survey, and was not incorporated into the published Sheet 217 (1929) even though the notes are incorporated into the published account of that Sheet (Richardson, 1929). Both the manuscript (MS) field maps (with geologist and date, where known) and, where applicable, the derivative fair-drawn 'standards' (with date of official release) are listed. Overall these older maps provide minimal information and are entirely superseded by those of the most recent survey.

Gloucs 21 NE/E Richardson/Welch c. 1927 1:10 560-scale MS field map (partial survey)

Gloucs 21 NE/E Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 21 SE/E Richardson/Welch c. 1927 1:10 560-scale MS field map (partial survey)

Gloucs 21 SE/E Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 22 NW/W Whitaker/Richardson 1:10 560-scale MS field map (notes only)

Gloucs 22 NW/W Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 22 NW/E Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 22 SW/W Whitaker/Richardson 1:10 560-scale MS field map (notes only)

Gloucs 22 SW/W Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 22 SW/E Whitaker/Richardson 1:10 560-scale MS field map (notes only)

Gloucs 22 SW/E Dines 1927 1:10 560-scale MS field map (partial survey)

Gloucs 21 NE Dines 1928 1:10 560-scale MS standard (partial survey)

Gloucs 21 SE Dines 1928 1:10 560-scale MS standard (partial survey)

Gloucs 22 NW Dines 1928 1:10 560-scale MS standard (partial survey)

Gloucs 22 SW Dines 1928 1:10 560-scale MS standard (partial survey)

SP 12 NE M G Sumbler 1996–97 1:10 000-scale MS field map (full survey)

SP 12 NE M G Sumbler 1997 1:10 000-scale MS standard (full survey)

9 References

ARKELL, W J. and DONOVAN, D T. 1952. The Fuller's Earth of the Cotswolds and its relation to the Great Oolite. Quarterly Journal of the Geological Society of London, Vol. 107, 227–253.

BARRON, A J M. 1998. Geology of the Hawling area (Sheet SP 02 SE). British Geological Survey Technical Report, WA/98/26/15

BARRON, A J M. 1999. Geology of the Naunton area (Sheet SP 12 SW). British Geological Survey Technical Report, WA/98/27.

BARRON, A J M, SUMBLER M G and MORIGI, A N. 1997. A revised lithostratigraphy for the Inferior Oolite Group (Middle Jurassic) of the Cotswolds, England. Proceedings of the Geologists' Association, Vol. 108, 269–285.

BENTON, M.J. and SPENCER, P.S. 1995. Fossil reptiles of Great Britain. Geological Conservation Review Series, No.10, Chapman and Hall, London.

BRIGGS, D J and COURTNEY, F M. 1972. Ridge-and-trough topography in the North Cotswolds. Proceedings of the Cotteswold Naturalists' Field Club, Vol. 36, 94–103.

COX, B M, SUMBLER, M G and IVIMEY-COOK, H C. 1999. A formational framework for the Lower Jurassic of England and Wales (Onshore Area). BGS Research Report No. RR/99/01.

HORTON, A, and POOLE, E G. 1977. The lithostratigraphy of three geophysical marker horizons in the Lower Lias of Oxfordshire. Bulletin of the Geological Survey of Great Britain, No. 62, 13–33.

HORTON, A, POOLE, E G, WILLIAMS, B J, ILLING, V C and HOBSON, G D. 1987. Geology of the country around Chipping Norton. Memoir of the British Geological Survey. Sheet 218 (England and Wales).

HULL, E. 1857. The geology of the country around Cheltenham. Memoir of the Geological Survey of Great Britain. (Old Series Sheet 44).

METCALF, S J, VAUGHAN, R F, BENTON, M J, COLE, J, SIMMS, M J and DARTNALL, D L. 1992. A new Bathonian (Middle Jurassic) microvertebrate site, within the Chipping Norton Limestone Formation at Homsleasow Quarry, Gloucestershire. Proceedings of the Geologists' Association, Vol. 103, 321–42.

REYNOLDS, S H. 1939. On a collection of reptilian bones for the Oolite of Stow-on-the-Wold, Gloucestershire. Geological Magazine, Vol. 76, 193–214.

RICHARDSON, L. 1904. Excursion to the Vale of Evesham and the north Cotteswolds. Proceedings of the Geologists' Association, Vol. 18, 391–408.

RICHARDSON, L. 1907. Excursion to Bourton-on-the-Water and Burford. Proceedings of the Cotteswold Naturalists' Field Club, Vol. 16, 23–32.

RICHARDSON, L. 1926. Excursion to the north Cotteswolds. Proceedings of the Cotteswold Naturalists' Field Club. Vol. 22, 67–73.

RICHARDSON, L. 1929. The Country around Moreton in Marsh. Memoir of the Geological Survey of Great Britain, Sheet 217 (England and Wales).

RICHARDSON, L. 1930. Wells and springs of Gloucestershire. Memoir of the Geological Survey of Great Britain.

SUMBLER, M.G. 1998a. Geology of the Icomb area (SP 22 SW). British Geological Survey Technical Report WA/98/15.

SUMBLER, M G. 1998b. Geology of the Moreton-in-Marsh area (SP 23 SW). British Geological Survey Technical Report, WA/98/53.

SUMBLER, M G. 1999a. Geology of the Bourton-on-the-Water area (SP 12 SE). British Geological Survey Technical Report, WA/99/07.

SUMBLER, M G. 1999b. Geology of the Oddington area (SP 22 NW). British Geological Survey Technical Report, WA/99/15.

SUMBLER, M G. 1999c.Geology of the Bourton-on-the-Hill area (SP13 SE). British Geological Survey Technical Report WA/99/27.

SUMBLER, M G. 1999d. Correlation of the Bathonian (Middle Jurassic) succession in the Minchinhampton-Burford district. Proceedings of the Geologists' Association, Vol. 110, 5358.

SUMBLER, M G. 2000.Geology of the Chalk Hill area (SP12 NW). British Geological Survey Technical Report WA/99/41.

SUMBLER, M G. in press. The Moreton Drift; a further clue to glacial chronology in central England. Proceedings of the Geologists' Association, Vol. 00, 00–00.

SUMBLER, M G. and Barron, A J M. 1996. The type section of the Hampen Formation (Middle Jurassic, Great Oolite Group) at Hampen Cutting, Gloucestershire. Proceedings of the Cotteswold Naturalists' Field Club, Vol. 40, 118–128.

SUMBLER, M G, BARRON, A J M and MORIGI, A N. 2000. Geology of the Cirencester district. Memoir of the British Geological Survey, Sheet 235 (England and Wales).

TORRENS, H S. 1969.The stratigraphical distribution of Bathonian ammonites in central England. Geological Magazine, Vol. 106, 63–76.

WOODWARD, H B. 1894. The Jurassic rocks of Britain. Vol.4 The Lower Oolitic rocks of England (Yorkshire excepted). Memoir of the Geological Survey of the United Kingdom.

WELCH, F B A. 1927. On the further extension of the Great Oolite in the north Cotteswolds. Proceedings of the Cotteswold Naturalists' Field Club, 22, 219–38.

WYATT, R J. 1996. A correlation of the Bathonian (Middle Jurassic) succession between Bath and Burford, and its relation to that near Oxford. Proceedings of the Geologists' Association, Vol. 107, 299–322.

Appendix 1 Sections

The localities described below are indicated on 1:10 000 Geological Sheet SP 12 NE. Thicknesses are given in metres. Some of the sections are paraphrased from other publications, but in all cases, stratigraphic classification is by MGS. Many of the older sections are noted by Richardson (1929) and are reproduced below; their sites are marked on his field maps (six-inch 'County' series, Gloucestershire 21) held in the BGS archives.

A. [SP 1567 2608] Swell Hill Quarry

Disused, partially infilled and overgrown quarry (MGS Oct, 1996):

B. [SP 1642 2639] Fenwick's Quarry

Old disused and partly infilled quarry, with face c. 100m long, but heavily overgrown. Beds dip at c. 3° to north-east (MGS, 7/10/1996):

Richardson (1929, p. 95) also recorded the section at this quarry, as paraphrased below:

C. [SP 1692 2654] Poles Plantation Quarry

Old shallow quarries, now heavily overgrown. There are considerable quantities of prepared tilestones amongst the waste material (MGS, October, 1996):

D. [SP 1507 2750] 'Quarry ⅓-mile south-east by east of Fox Farm'

This quarry is now entirely infilled, and the ground restored to agriculture. The following is based on Richardson (1929, p. 94):

E. [SP 1570 2789] 'Quarry ⅓-mile south-east of Condicote'

This quarry, now marked only by a depression in the field, was recorded by Richardson (1929, p. 94):

F. [SP 1615 2762] Flagstone Quarry

Old quarry, now largely infilled and overgrown. The following section is based on Richardson (1929, p. 95):

Richardson (1929) stated that the lower unit of limestone yielded flagstones. These were worked from a mine that went under the road; a second mine entrance was visible in the western part of the quarry.

G. [SP 1665 2724] Guiting Road Cutting

Old quarry incorporated into road cutting (MGS 8/10/1997):

The classification of bed 1 is somewhat tentative; its lithology and the presence of an eroded top surface is certainly suggestive of Chipping Norton Limestone, although this makes the thickness of the Taynton Limestone Formation at this locality unusually small.

It seems likely that the 'pebbles' lie at the base of bed 2 of the current section. Richardson mistakenly classified the whole section as Chipping Norton Limestone.

H. [SP 1540 2823] Condicote Quarry

The quarry is now entirely infilled, and the Condicote village hall is built on the site. The following is based on Richardson's section (field map Gloucestershire 21 NE/E):

Richardson described the lower part of the section as 'like Chipping Norton Limestone' and it is probable that the quarry extended down into that formation.

I. [SP 1511 2935] Debdene Quarry

Small disused and partly infilled quarry (MGS, April, 1997):

J. [SP 1609 2882] Luckley Farm Quarry

Old disused quarry now used as a loading and parking area (MGS 8/4/1997).

K. [SP 1616 2889] Luckley Farmyard

Small face (part of former quarry?) surmounted by a wall (MGS, April, 1997).

L. [SP 1630 2993] Sezincote Hill Quarry

Old quarry near the former Sezincote Hill Farm, now called Hans Hill Farm, though indicated as Hans Hill Farm on some Ordnance Survey maps. There is now no exposure; the following section is based on Richardson (1929, p. 72):

M. [SP 1626 2997] to [SP1614 3003] Hans Hill Farm

The following section (which extends onto Sheet SP 13 SE) was recorded by Richardson (field map Gloucestershire 21NE/E) as 'section in well and descending trench to pond'.

Richardson (1929, p. 72) classified the section as Snowshill Clay, succeeded by Tilestone. There is currently no exposure here.

N. [SP 171 295] Longborough Quarry

Ancient quarry workings covering an area of c. 2.5 hectares, now covered by mature woodland. Modest exposures on western side, and good but dangerous faces on the north side, where the quarry is c. 10m deep. There [SP 1712 2958] the section shows (MGS, April, 1997):

Woodward (1894, p. 143) gave the following section, repeated by Richardson (1929, p. 72):

O. [SP 1744 2816] New Park Quarry, Longborough

This SSSI/GCR site in the fossil reptile network (Benton and. Spencer, 1995) is disused and contains a large grain store. It nevertheless shows an excellent section particularly on the west side (MGS 21/10/1996):

Richardson (1929 p. 89) gave the following section:

A section by W J Arkell (in Arkell and Donovan, 1952 p. 249) is as follows:

From its 'nodular' character, it is likely that Arkell's fossiliferous Bed 2 corresponds with Bed 2 of the present author.

P. [SP 1733 2770] Donnington Brewery road cutting roadside section opposite entrance to brewery (MGS 10/4/1997):

Q. [SP 1677 2517] Lower Swell Quarry

Disused quarry, now largely infilled and heavily overgrown. This quarry is briefly mentioned by Richardson (1904, p. 25; 1929, p. 117) and a section given by Richardson (1907, p. 25) and in a somewhat different version on field map Gloucestershire 22SW/VV.

From the presence of the thick marly beds, and abundant oysters 'of the 0. sowerbyi type' (i.e. Praeexogyra hebridica) with large rhynchonellids, Richardson (op cit.) not unreasonably classified the strata as the Wally Beds' of the Great Oolite, i.e. Hampen Formation. However, mapping shows that the site lies on the outcrop of the Cleeve Cloud Member, and the remaining section, in the highest part of the quarry shows 0.3m of yellow-white fine- to medium-grained oolite typical of that member. Whilst it is just possible that a small 'wedge' of Hampen Formation could be downfaulted in the remaining part of the quarry, it seems more likely that the strata are an unusual local development in the Cleeve Cloud Member.

R. [SP 1876 2774] Stonehill Quarry

Fairly extensive abandoned quarry. Limited exposure remains in the south face, adjoining the road (MGS, October 1996)

S. [SP 1884 2770] Stonehill Quarry No 2.

This quarry was recorded by Richardson (1929, p. 113); its location is indicated on his field map Gloucestershire 22SW/W. It is now entirely infilled and restored:

Richardson (1929, p. 89; 113) erroneously classified the top three beds as Taynton Limestone Formation.

T. [SP 1931 2717] Quarry 'west of Fosse Way Cutting'

This quarry is now entirely infilled and restored; the section was recorded by Richardson. (1979 n 7T)

U. [SP 1933 2716] to [SP1937 2729] Fosse Way road cutting a composite section showed (MGS 17/10/1996):

Due to northward component of dip, the oldest beds are seen at the southern (uphill) end of the section.

Richardson (1929, p. 73–74) recorded:

Farther north, on the east side of the cutting [SP 1943 2733], Richardson recorded 0.76m of 'Yellow Stone', i.e. Cleeve Cloud Member, but mapping suggests that the material he saw there is in fact Chipping Norton Limestone.

V. [SP 1946 2743] Triangle Quarry

This quarry is now largely infilled and overgrown. Richardson (1929, p. 72) recorded:

W. [SP 1859 2580] Stow Quarry

This disused and restored quarry is probably that referred to by Woodward (1894, p. 144):

The Clypeus Grit below was probably observed in the adjoining road cutting to the west.

X. [SP 1862 2603] Abbotswood

Natural section in stream (MGS, October, 1997):

Tables

(Table 1) Geological sequence proved within sheet SP 12 NE (Stow on the Wold)

(giving estimated thicknesses in metres)