The BGS Lexicon of Named Rock Units — Result Details

Beer Head Limestone Formation

Computer Code: BRHD Preferred Map Code: notEntered
Status Code: Full
Age range: Cenomanian Age (KE) — Cenomanian Age (KE)
Lithological Description: Complex thin sequence of bedded coarse calcareous sandstone, bioclastic limestone, calcarenite and shell-detrital limestone, with a distinct nodularity and well-developed hardgrounds. Glauconitic and phosphatic. Includes the Wilmington Sand Member in calcarenite facies. Subdivision: None included here, but defined by Jarvis and Woodroof (1984) as comprising the Pounds Pool Sandy Limestone, Hooken Nodular Limestone and Little Beach Bioclastic Limestone members of the Beer Head Limestone Formation .
Definition of Lower Boundary: The lower boundary is disconformable and placed at the burrowed surface on the top of the Small Cove Hardground of the Upper Greensand Formation. The yellow brown very coarse-grained calcareous sandstone of the Pounds Pool Sandy Limestone ("Member") rests on this hardground surface.
Definition of Upper Boundary: The upper boundary is disconformable at the surface of the Humble Point Hardground with the Pinnacles Member (of Jarvis and Woodroof, 1984), which is the sub-Plenus Marls Member erosion surface.
Thickness: Up to 10.4 m at Hooken Cliffs.
Geographical Limits: Confined to the area south of the mid-Dorset Swell in Dorset.
Parent Unit: Grey Chalk Subgroup (GYCK)
Previous Name(s): Little Beach Bioclastic Limestone Member [Obsolete Name and Code: Use BRHD] (*745)
Hooken Nodular Limestone Member [Obsolete Name and Code: Use BRHD] (*381)
Pounds Pool Sandy Limestone Member [Obsolete Name and Code: Use BRHD] (*21)
Cenomanian Limestone [Obsolete Name and Code: Use BRHD] (-2637)
Chalk Marl [Obsolete Name and Code: Use WMCH, BRHD] (CKM)
Little Beach Bioclastic Limestone Member [Obsolete Name and Code: Use BRHD] (*745)
Hooken Nodular Limestone Member [Obsolete Name and Code: Use BRHD] (*381)
Pounds Pool Sandy Limestone Member [Obsolete Name and Code: Use BRHD] (*21)
Chloritic Marl [Obsolete Name and Code: Use BRHD, CBG, GLML] (-4494)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Hooken Cliffs [SY 210 881 to 227 878], Devon. Shows the entire succession of the formation. See Mortimore et al. (2001). 
Reference Section  Wilmington Quarry, Devon. The quarry shows the lateral equivalent sandy facies of the formation, the so-called Wilmington Sands (member in Mortimore et al., 2001). 
Reference Section  Beer Head, Devon. The headland shows a condensed succession of the formation in the cliffs. see Mortimore et al. (2001). 
Reference(s):
Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. 
Mortimore, R N, Wood, C J and Gallois, R W, 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review Series. No. 23. (Peterborough: Joint Nature Conservation Committee.) 
Jarvis, I and Woodroof, P B. 1984. Stratigraphy of the Cenomanian and basal Turonian (Upper Cretaceous) between Branscombe and Seaton, SE Devon, England. Proceedings of the Geologists' Association, Vol.95, 193-215. 
Jukes-Browne, A J and Hill, W. 1896. A delimitation of the Cenomanian:- being a comparison of the corresponding beds in south-western England and western France. Quarterly Journal of the Geological Society, Vol.52, 99-177. 
Meyer, C J A. 1874. On the Cretaceous rocks of Beer Head and the adjacent cliffs, and of the relative horizons therein of the Warminster and Blackdown fossiliferous deposits. Quarterly Journal of the Geological Society, Vol.30, 369-393. 
Smith, W E. 1965. The Cenomanian deposits of south-east Devonshire. The Cenomanian limestone east of Seaton. Proceedings of the Geologists' Association, Vol.76, 121-136. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable