The BGS Lexicon of Named Rock Units — Result Details

Clavellata Formation

Computer Code: CLAV Preferred Map Code: ClB
Status Code: Full
Age range: Oxfordian Age (JO) — Oxfordian Age (JO)
Lithological Description: Variable from bioclastic oolite, fine- to medium-grained oolite, biomicrite, with thin beds of marl, sandy marl and fine-grained sand.
Definition of Lower Boundary: Usually a coarse shelly oolite, resting (locally with angular discordance) on fine, evenly graded oolite of the Todber Freestone (where present), or on clay and sandy clay of the Newton Clay.
Definition of Upper Boundary: Fairly abrupt change to sandy clays and clayey sands of the Sandsfoot Formation.
Thickness: 3 - 7m
Geographical Limits: From the middle of the Wincanton Sheet (297), southwards across the whole of the Shaftesbury Sheet (313). Almost certainly it is the same as the Trigonia Clavellata Beds of the Dorset coast.
Parent Unit: Corallian Group (CR)
Previous Name(s): Trigonia Clavellata Beds [Obsolete Name And Code: Use CLAV] (TCLB)
Clavellata Beds Formation [Obsolete Name and Code: Use CLAV] (*710)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Old quarries [ST 7949 1980, 796 199, 7975 1990, 7970 1973, 796 197, 8015 2003, and 8030 2005] around Todber, Dorset. 
Reference Section  New quarry, White Way Hill, Marnhull. 
Reference(s):
Bristow, C R, 1989. Geology of Sheets 71NE and 71SE. (Marnhull-Sturminster Newton, Dorset) Part of 1:10,000 Sheet 313 (Shaftesbury). British Geological Survey Technical Report WA/89/59. 
Freshney, E C. 1989. Geology of Sheets ST70NW and ST70NE. (Hazelbury Bryan-Mappowder district, Dorset). British Geological Survey Technical Report WA/90/51. 
Gutmann, K, 1970. The Corallian Beds at Todber and White Way Hill in north Dorset. Proceedings of Dorset Natural History and Archaeological Society, Vol.91, p.123-133. 
Wright, J K, 1981. The Corallian rocks of north Dorset. Proceedings of the Geologists' Association, Vol.92, 17-32. 
Bristow, C R, 1990. Geology of the West Stour - Cucklington district. British Geological Survey Technical Report WA/90/48. 
Bristow, C R, 1989. Geology of the East Stour - Shaftesbury district (Dorset) British Geological Survey Technical Report WA/89/58. 
Arkell, W J. 1933. The Jurassic System in Great Britain [Oxford: Clarendon Press.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E297 E313 E281 E341 E342 E343 E327