The BGS Lexicon of Named Rock Units — Result Details

Gray Sandstone Group

Computer Code: GSA Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Wenlock Epoch (SW) — Wenlock Epoch (SW)
Lithological Description: Green-grey yellow weathering hard quartzitic sandstones and tough mudstones, fossiliferous within decalcified sandy rottenstone.
Definition of Lower Boundary: Drawn at the base of the Gray Sandstone Group where it rests conformably upon the Coralliferous Group.
Definition of Upper Boundary: Drawn at the conformable upward passage from the Gray Sandstone Group to the Red Marls Formation of the Lower Old Red Sandstone.
Thickness: 274m to 609m approximately.
Geographical Limits: Pembrokeshire coast, Dyfed, southwest Wales.
Parent Unit: Not Applicable (-)
Previous Name(s): Grey Sandstone Series (-2835)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Milford coast, Dyfed. 
Reference(s):
Cocks, L R M, Holland, C H, Rickards, R B and Strachan, I, 1971. A correlation of Silurian rocks in the British Isles. Geological Society of London, Special Report No.1. 
Mabillard, J E and Aldridge, R J, 1983. Conodonts from the Coralliferous Group of Marloes Bay, South-West Dyfed, Wales. Geologica et Palaeontologica, Vol.17, p.29-43. 
St Joseph, J K S. 1935. A critical examination of Stricklandia lirata (J de C Sowerby) 1839, forma typica. Geological Magazine. Vol.72, 421-422. 
Jones, O T, 1921. The Valentian Series. Quarterly Journal of the Geological Society, Vol.77, p.154-157. 
De La Beche, H. 1846. On the formation of rocks of south Wales and south-west England. Memoir of the Geological Survey of Great Britain, No.1. 
Cantrill, T C and others, 1916. South Wales Coalfield, part XII, Milford. Memoir of the Geological Survey of Great Britain. 
Walmsley, V G and Bassett, M G, 1976. Biostratigraphy and correlation of the Coralliferous Group and Grey Sandstone Group of Pembrokeshire, Wales. Proceedings of the Geologists' Association, Vol.887, 191-220. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable