The BGS Lexicon of Named Rock Units — Result Details

Ravenhead Rock

Computer Code: RHR Preferred Map Code: notEntered
Status Code: Full
Age range: Langsettian Substage (CA) — Langsettian Substage (CA)
Lithological Description: Sandstone and pebbly sandstone, part-reddened, medium-to-coarse-grained, micaceous, with well-defined soft hematic partings, and subordinate mudstone. A basal pebbly sandstone may be present, comprising clasts of mudstone and ironstone up to 2 feet in diameter.
Definition of Lower Boundary: The lower boundary is taken at a well-defined erosional surface. The base is taken at the base of the first sandstone unit above the Wigan 4 foot Coal, or where this is absent, the base of the first sandstone unit overlying the Wigan 5 foot Coal.
Definition of Upper Boundary: The upper boundary is taken at the base of a mudstone-dominated succession of the Pennine Lower Coal Measures Formation above the sandstone of the Ravenhead Rock.
Thickness: From 21m to 46m
Geographical Limits: Southern and western parts of the South Lancashire Coalfield.
Parent Unit: Pennine Lower Coal Measures Formation (PLCM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Lindsey Pit, Whelley, Wigan (359630 406920), which displays an exposure of basal pebbly sandstone. Jones et al,. 1938. 
Type Section  Ellerbeck Borehole [SD51SE/10] (359030 414200), between 56 feet and 132 feet 3 inches below ground level. Both the top and base of formation are proved. Price et al., 1963. 
Reference(s):
Jones, R C B, Tonks, L H and Wright, W B, 1938. Wigan District. Memoir of the Geological Survey of Great Britain. England and Wales Sheet 84. 
Price, D, Wright, W B, Jones, R C B, Tonks, L H and Whitehead, T H. 1963. Geology of the country around Preston. Memoir of the Geological Survey of Great Britain, Sheet 75 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E084 E075 E097