The BGS Lexicon of Named Rock Units — Result Details

Lower Coal Measures Formation [Obsolete Name And Code: Use PLCM, SWLCM, LCMS]

Computer Code: LCM Preferred Map Code: LCM
Status Code: Index Level
Age range: Langsettian Substage (CA) — Langsettian Substage (CA)
Lithological Description: Grey mudstone, siltstone and pale grey sandstone interbedded; coal seams common in upper part; mudstones with marine fossils (marine bands) present in lower part.
Definition of Lower Boundary: At base of mudstone of Subcrenatum Marine Band, or at base of lowest coal of the coal-bearing sequence if this marker band cannot be recognised.
Definition of Upper Boundary: At base of mudstone of Vanderbeckei Marine Band.
Thickness: Up to 650 m (Potteries Coalfield,North Staffordshire) ; more (720 m) in Lancashire.
Geographical Limits: Central and northern England and North Wales.
Parent Unit: Coal Measures Group (CM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Reference Section  For base and lower part. Ridgeway Borehole (SJ85SE/14) [SJ 8923 5381], down to 1806ft 10ins. SJ85SE/14. 
Reference Section  For top part; Hesketh Back Crut (Crosscut) [SJ 884 533], Chatterley Whitfield Colliery,Stoke on Trent, depth 2100ft to 1045ft in constructed stratigraphic section (V5 British Coal, G7 British Geological Survey). 
Reference Section  For top boundary; Miry Wood, Apedale [SJ 8118 4940] - to be a designated RIGS - mudstone of Vanderbeckei Marine Band. 
Type Area  Potteries Coalfield, Stoke on Trent, North Staffordshire; numerous borehole and shaft sections, not many exposures.[SJ 5090]. 
Rees, J G and Wilson, A A. 1998. Geology of the country around Stoke-on-Trent. Memoir of the British Geological Survey, Sheet 123 (England and Wales). 
Stubblefield, C J and Trotter, F M, 1957. Divisions of the Coal Measures on Geological Survey Maps of England and Wales. Bulletin of the Geological Survey of Great Britain, No.13, p.1-5. 
Powell, J H, Chisholm, JI, Bridge, D M, Rees, J G, Glover, B W and Besly, B M. 1999. Stratigraphical framework for Westphalian to Early Permian red-bed successions of the Pennine Basin. British Geological Survey Technical Report WA/99/10. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E059 E167 E141 E019 E025 E281 E096 E123 E126 E077 E262 E249 E248 E247 E244 E245 E232 E231 E078 E139 E154 E086 E021 E010 E014 E081 E090 E091 E032 E026 E023 E015 E027 E114 E127 E070 E142 E022 E024 E028