The BGS Lexicon of Named Rock Units — Result Details

Middle Coal Measures Formation [Obsolete Name And Code: Use PMCM, MCMS, SWMCM]

Computer Code: MCM Preferred Map Code: MCM
Status Code: Index Level
Age range: Duckmantian Substage (CB) — Bolsovian Substage (CC)
Lithological Description: Grey mudstone, siltstone and pale grey sandstone interbedded; coal seams common mudstone with marine fossils; (marine bands) present in the upper half and a single one at base.
Definition of Lower Boundary: At base of mudstone of Vanderbeckei Marine Band.
Definition of Upper Boundary: At top of mudstone of Cambriense Marine Band.
Thickness: Up to c.680m in Potteries Coalfield, North Staffordshire; more (to c.750m) 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
Stratotypes:
Reference Section  For base and lower part. Hesketh Back Crut, Chatterley Whitfield Colliery (Crosscut) [SJ 884 553]. Depth 1045ft to top of section in constructed stratigraphic section (V5 British Coal, G7 British Geological Survey log). 
Reference Section  For base. Miry Wood, Apedale [SJ 8118 4940] - to be a designated RIGS - Vanderbeckei Marine Band. 
Type Area  Potteries Coalfield, Stoke on Trent; numerous borehole and shaft sections, not many exposures [SJ 5090]. 
Reference Section  For upper part. Holditch Colliery. No.4 underground borehole (SJ84NW/30) [SJ 8392 4850], 657ft to 1068ft. Below Rowhurst Coal to top of Cambriense Marine Band. 
Reference Section  For top. Parkhouse Colliery No.1 underground bore Stoke on Trent at 529ft depth - top of Cambriense Marine Band. SJ85SW/19 [SJ 8396 5029]. 
Reference(s):
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. 
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. 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E123 E126 E077 E262 E249 E248 E247 E232 E231 E078 E154 E021 E010 E014 E020 E081 E090 E091 E032 E026 E023 E015 E027 E114 E127 E070 E217 E142 E022 E028 E167 E141 E019 E025 E281 E264 E096 E009 E018 E031 E050 E084 E085 E087 E097 E098 E100 E108 E110 E112 E124 E125 E152 E153 E155 E168 E169