The BGS Lexicon of Named Rock Units — Result Details

Worston Shale Group [Obsolete Name And Code: Part Of CRAV]

Computer Code: WSG Preferred Map Code: WrSh
Status Code: Index Level
Age range: Chadian Substage (CI) — Asbian Substage (CR)
Lithological Description: Predominantly calcareous mudstones, interbedded with limestones (commonly pale grey and coarsely bioclastic in the lower part), subordinate siltstones, limestone breccias and conglomerates, and sandstone. Bioturbation and soft sediment deformation are common, the latter mainly in the middle and upper part of the group.
Definition of Lower Boundary: Underlain by the Chatburn Limestone Formation (formerly Group).
Definition of Upper Boundary: Overlain by the Bowland Shale Formation.
Thickness: To 1700m
Geographical Limits: Craven Basin.
Parent Unit: Not Entered (?)
Previous Name(s): Worston Shales [Obsolete Code: Use WSG] (WRSH)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Clitheroe Road cut, Worston, near Clitheroe, Lancashire). Lowest formation (Clitheroe Limestone Formation). 
Reference(s):
Earp, J R, Magraw, D, Poole, E G, Land, D H and Whiteman, A J, 1961. Geology of the country around Clitheroe and Nelson. Memoir of the Geological Survey of Great Britain, Sheet.68, England and Wales, pp.346. 
Riley N J. 1990. Stratigraphy of the Worston Shale Group (Dinantian) Craven Basin, north-west England. Proceedings of the Yorkshire Geological Society, Vol. 48, 163-187. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E060