The BGS Lexicon of Named Rock Units — Result Details

Leagram Mudstone Member

Computer Code: LEAM Preferred Map Code: notEntered
Status Code: Full
Age range: Chadian Substage (CI) — Chadian Substage (CI)
Lithological Description: A dark grey, blocky, pyritic and calcareous mudstone, interbedded with thin, dark wackestones with diffuse bed boundaries.
Definition of Lower Boundary: The dark grey blocky mudstone of the Leagram Mudstone Member lies conformably upon limestones of the Limekiln Wood Limestone Member in the Clitheroe Anticline or upon the Whitemore Limestone Member of the Whitewell Anticline.
Definition of Upper Boundary: At the type locality, taken where there is a change from the dark grey blocky mudstone of the Leagram Mudstone Member to the overlying thin-bedded, laminated calcisiltites and dark grey, fissile mudstones of the Hodder Mudstone Formation (undifferentiated).
Thickness: Up to at least 50 m thick.
Geographical Limits: Restricted to the Clitheroe (SD 75 45), Slaidburn (SD 71 53) and Whitewell (SD 64 47) anticlines.
Parent Unit: Hodder Mudstone Formation (HOM)
Previous Name(s): Prolecanites Compressus Beds (-4155)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Leagram Brook, meander cliff on east bank (SD 6375 4450), 1.97 km NE of Chipping Parish Church. The base of the member is not exposed; discontinuous exposures occur upstream to the top of the member exposed at a stream confluence (SD6357 4457). Riley, 1990. 
Reference(s):
Riley N J. 1990. Stratigraphy of the Worston Shale Group (Dinantian) Craven Basin, north-west England. Proceedings of the Yorkshire Geological Society, Vol. 48, 163-187. 
Parkinson, D, 1926. The faunal succession in the Carboniferous Limestone and Bowland Shales at Clitheroe and Pendle Hill, Lancashire. Quarterly Journal of the Geological Society of London. Volume 82. p.188-249. 
Aitkenhead, N, Bridge, D M, Riley, N J and Kimbell, S F. 1992. Geology of the country around Garstang. Memoir of the British Geological Survey, Sheet 67 (England and Wales) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E060 E067 E068