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
Stratotypes:
none recorded or not applicable
Reference(s):
Cave R. 1977. Geology of the Malmesbury District. Memoir of the Geological Survey of Great Britain, Sheet 251 (England and Wales). 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E216 E234