The BGS Lexicon of Named Rock Units — Result Details

Scottish Coal Measures Group

Computer Code: CMSC Preferred Map Code: CMSC
Status Code: Pending Upgrade
Age range: Langsettian Substage (CA) — Bolsovian Substage (CC)
Lithological Description: Cyclic alternation of mudstone, siltstone and sandstone with common coal seams at some levels. NOTE: FORMERLY - (1) Upper (Barren) Coal Measures. (2) Productive Coal Measures (comprising Middle Coal Measures and Lower Coal Measures). The Coal Measures of England and Wales were defined by Stubblefield and Trotter, 1957, and divided into Upper, Middle and Lower with their respective bases at the Cambriense, Vanderbeckei and Subcrenatum marine bands. MacGregor, 1960, divided the Scottish Coal Measures into Upper (Barren), with base at the Aegiranum marine band, Middle, with base at the Vanderbeckei marine band and Lower which, in the apparent absence of the Subcrenatum marine band in Scotland, he proposed should have its base at a suitable arbitrary line. The position taken for this line in different coal basins is shown in Ramsbottom, et al. 1978. It is proposed that these local bases of the Lower Coal Measures, and the boundaries defined by MacGregor for the Middle and Upper Coal Measures be retained. The long standing terms should be retained but since only the Middle Coal Measures is fully defined, they are regarded as informal. As the terms are applied differently in England and Wales, it is proposed that Scotland should be added to Coal Measures in parenthesis. The terms "Barren" and "Productive" are misleading in a Scottish context and should be dropped.
Definition of Lower Boundary: Different in different areas. (See notes in lithology).
Definition of Upper Boundary: Unconformity at base of Permian or younger rocks.
Thickness: Variable
Geographical Limits: Midland Valley of Scotland, and adjacent areas.
Parent Unit: Coal Measures Supergroup (COME)
Previous Name(s): Coal Measures Group (CM)
Barren Coal Measures (Upper) (-146)
Coal Measures Group (Scotland) (-797)
Productive Coal Measures (Middle And Lower) (-2104)
Leswalt Formation [Obsolete Name And Code: Use CMSC] (LWT)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Strathclyde, Lothian, Fife, Scotland. (Midland Valley of Scotland). 
Reference(s):
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. 
Waters, C N, Waters, R A, Barclay, W J, and Davies, J R. 2009. Lithostratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/09/01. 184pp. 
Ramsbottom, W H C, Calver, M A, Eagar, R M C, Hodson, F, Holliday, D W, Stubblefield, C J and Wilson, R B. 1978. A correlation of the Silesian rocks in the British Isles. Geological Society of London, Special Report No.10. 
MacGregor, A G, 1960. Division of the Carboniferous on Geological Survey Scottish Maps. Bulletin of the Geological Survey of Great Britain, No.16, 127-130. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S015 S006 S011 S338 S023 S033 S040 S030 S039 S044