| 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 [Obsolete Name and Code: Use GSA]
(-2835)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Milford coast, Dyfed. |
| Reference(s): |
| 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. |
| Jones, O T, 1921. The Valentian Series. Quarterly Journal of the Geological Society, Vol.77, p.154-157. |
| 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. |
| 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 |
