The BGS Lexicon of Named Rock Units — Result Details

Lower Lias Clay Formation [Obsolete Name And Code: Use CHAM]

Computer Code: LLIC Preferred Map Code: LLi
Status Code: Index Level
Age range: Sinemurian Age (JS) — Pliensbachian Age (JE)
Lithological Description: Grey, blocky and fissile, fossiliferous mudstones with some thin limestones.
Definition of Lower Boundary: Placed at base of mudstones where they overlie the topmost limestone bed of the Rugby Limestone Member of the Blue Lias Formation.
Definition of Upper Boundary: Transitional, passing upwards into the Dyrham Siltstone Formation.
Thickness: About 250m in Worcester Basin.
Geographical Limits: Gloucestershire - Worcestershire.
Parent Unit: Lias Group (LI)
Previous Name(s): Lower Lias Clay (-1661)
Lower Lias Clays (-1031)
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Cope, J C W and others, 1980. A correlation of Jurassic rocks in the British Isles. Part 1: Introduction and Lower Jurassic. Special Report of the Geological Society of London, No.14. 
Worssam, B C, Ellison, R A and Moorlock, B S P. 1989. Geology of the country around Tewkesbury. Memoir of the British Geological Survey, Sheet 216 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E216 E249 S013