The BGS Lexicon of Named Rock Units — Result Details

Upper Lias Clay Formation [Obsolete Name And Code: Use WHM]

Computer Code: ULC Preferred Map Code: ULi
Status Code: Index Level
Age range: Toarcian Age (JT) — Toarcian Age (JT)
Lithological Description: Mainly grey, silty mudstones, fossiliferous, with some siltstones.
Definition of Lower Boundary: Placed at junction of mudstones with underlying Marlstone Rock Formation.
Definition of Upper Boundary: Placed at base of overlying Inferior Oolite Group (Worcestershire) and base of Midford Sands (Bristol district) and Cotteswold Sands (Malmesbury district).
Thickness: c.120m
Geographical Limits: Gloucestershire, Avon, Worcestershire.
Parent Unit: Lias Group (LI)
Previous Name(s): Clay In Upper Lias (-3106)
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Formal definition not published. 
Donovan, D T and Kellaway, G A 1984. Geology of the Bristol district: Lower Jurassic rocks. Memoir of the British Geological Survey, Bristol Special Sheet (England and Wales). 
Cave R. 1977. Geology of the Malmesbury District. Memoir of the Geological Survey of Great Britain, Sheet 251 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E216 E234