The BGS Lexicon of Named Rock Units — Result Details

Mill Lane Limestones Bed

Computer Code: MLLL Preferred Map Code: ML
Status Code: Full
Age range: Sinemurian Age (JS) — Sinemurian Age (JS)
Lithological Description: Two grey, weathering brown, sandy, shelly limestone or highly calcareous siltstone beds up to c 0.3m thick, separated by up to 1m of mudstone. Limestone/siltstone becoming nodular in south of range. Fauna includes gastropods, brachiopds, bivalves (including numerous pectiniids and common Gryphaea), ammonites, belemnites, ostracods and echinoderms. Forms a variably strong feature.
Definition of Lower Boundary: Change up from grey mudstone with large limestone nodules of undifferentiated Foston Member; at 19.58m depth in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17)
Definition of Upper Boundary: Change up into grey mudstone with thin impersistent limestone beds of undifferentiated Foston Member; at 18.51m depth in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17)
Thickness: 0 to 1.1m; 1.07m in type section.
Geographical Limits: East Midlands: north Leicestershire to Linclonshire. Not recognised in the Scunthorpe Mudstone Formation of north Lincolnshire, or south Leicestershire, where it passes south either into part of the more argillaceous Rugby Limestone Member of the Blue Lias Formation or into part of the mudstone-dominated Charmouth Mudstone Formation.
Parent Unit: Foston Member (FSTL)
Previous Name(s): Mill Lane Limestone (-2941)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Fulbeck Airfield Borehole F/B5 (SK95SW/17). 
Reference(s):
Brandon, A, Sumbler, M G and Ivimey-Cook, H C, 1990. A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, England. Proceedings of the Yorkshire Geological Society, Vol.48, 121-141. 
Carney, J N, Ambrose. K and Brandon A, 2002. Geology of the Melton Mowbray district - a brief explanation of the geological map. British Geological Survey Sheet Explanation, Sheet 142 (England and Wales). 
Berridge, N G, Pattison, J, Samuel, M D A, Brandon, A, Howard, A S, Pharaoh, T C and Riley, N J. 1999. Geology of the Grantham district. Memoir of the British Geological Survey, sheet 127 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E127 E142 E126