The BGS Lexicon of Named Rock Units — Result Details

Cefn Rock

Computer Code: CF Preferred Map Code: notEntered
Status Code: Index Level
Age range: Bolsovian Substage (CC) — Bolsovian Substage (CC)
Lithological Description: Massive, quartzose sandstone with subordinate and impersistent beds of mudstone and coal.
Definition of Lower Boundary: A sharp contact with underlying measures of the Pennine Middle Coal Measures Formation, which overlies an unnamed coal in its type area.
Definition of Upper Boundary: Contact with overlying measures of Pennine Middle Coal Measures Formation.
Thickness: Up to 37 m thick.
Geographical Limits: Denbighshire Coalfield (SJ 30 50).
Parent Unit: Pennine Middle Coal Measures Formation (PMCM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Sandstone ridge between Garden Lodge, in the north, and Cefn-mawr, in the south, located between the Cefn & Minera faults. Wedd C B. 1928. 
Reference(s):
Wedd, C B, Smith, B and Wills, L J. 1927. The geology of the country around Wrexham, Part 1. Lower Palaeozoic and Lower Carboniferous rocks. Memoir of the Geological Survey of Great Britain. [London: HMSO.] 179pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E121