The BGS Lexicon of Named Rock Units — Result Details

Middle Coal (Radstock Member, Somerset)

Computer Code: MDDC Preferred Map Code: notEntered
Status Code: Index Level
Age range: Asturian Substage (CAS) — Asturian Substage (CAS)
Lithological Description: Coal, with a high clastic content, containing thick dirt partings where it splits in two, in the east of the subcrop.
Definition of Lower Boundary: Taken at the base of the coal, resting on mainly grey mudstone of the underlying undivided Radstock Member.
Definition of Upper Boundary: Taken at the top of the coal, overlain by a hard mudstone and sandstone both of the undivided Radstock Member. Elsewhere the unit is capped by a shale roof.
Thickness: A thin coal, from about 36 cm around Timsbury [366862 158 974], to 66 cm thick in the west of the Somerset Coalfield, near where it dips below the sub-Triassic outcrop, and also around Radstock [367195 153 272] in the south of the coalfield. To the east of the coal basin, the seam splits in two, and attains a combined thickness of about 75cm.
Geographical Limits: Identified across the North Somerset Coalfield, in the Radstock and Pensford basins and may extend as far north as Brislington, although it is not exposed at the surface. It has been mined at the Radstock and Clandown collieries, where it has a certain uniformity of thickness. It may correlate with the similarly appearing Grovesend Formation, logged as Upper Coal Measures in the Apley Barn borehole SP31SW/3 (434370, 210660), near Witney, in the concealed Oxfordshire Coalfield.
Parent Unit: Radstock Member (RAD)
Previous Name(s): Middle Coal (Somerset) (-1056)
Middle Vein (-3549)
Alternative Name(s): Pensford No. 2
No. 5 Vein
Stratotypes:
none recorded or not applicable
Reference(s):
Kellaway, G A. 1967. The correlation of the Upper Coal Measures of the Forest of Dean, Bristol and Somerset coalfields with those of the Midlands of England. In: Abstracts [of the] 6th International Congress of Carboniferous Stratigraphy and Geology, Sheffield, 1967. 
Kellaway, G A and Welch, F B A, 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. 
Collier, P. 1986. Collier's Way: History and walks in the Somerset Coalfield. [Bradford-on-Avon: Ex-Libris Press.] 
Down, C G and Warrington, A J. 1971. The history of the Somerset Coalfield. [Newton Abbot: David and Charles.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E280 E281 E264