The BGS Lexicon of Named Rock Units — Result Details

St Bees Shale Formation

Computer Code: SBSH Preferred Map Code: SBSh
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: Mainly red siltstones and silty mudstones, with some sandstone, millet-seed sand grains, mudstone breccias and gypsum.
Definition of Lower Boundary: 'The base of the main red clastic sequence', where red mudstones become predominant over the evaporites that characterise the underlying formation (St. Bees Evaporites).
Definition of Upper Boundary: Taken where sandstone, which characterises the overlying formation (St. Bees Sandstone), becomes predominant over red siltstone and mudstone.
Thickness: 62m in type section with range of 0 - 215m in Cumbria generally.
Geographical Limits: West and south Cumbria, north Lancashire, East Irish Sea Basin.
Parent Unit: Cumbrian Coast Group (CCO)
Previous Name(s): St Bees Shales Formation (-1163)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Borehole NX91SE/190 (Sandwith S9) 1.4km southwest of Salton Bay, west Cumbria. Depth 99.0 to 160.9m. (Arthurton and Hemingway, 1972). 
Reference(s):
Arthurton, R S and Hemingway, J E, 1972. The St Bees Evaporites - a carbonate evaporite formation of Upper Permian age in west Cumberland, England. Proceedings of the Yorkshire Geological Society, Vol.38, p 565-591. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E058 E018 E022 E011 S006 E028 E048 E012