| Computer Code: |
CRBS |
Preferred Map Code: |
Cbw |
| Status Code: |
Pending Upgrade |
| Age range: |
Comley Series (EC)
— St David's Series (ED) |
| Lithological Description: |
Fine-grained purple micaceous and feldspathic sandstones, pebbly near the top, with thin mudstone interbeds. |
| Definition of Lower Boundary: |
Conformably overlies the mudstones of the Caerfai Bay Shales Formation. |
| Definition of Upper Boundary: |
Overlain by greenish grey sandstones of the Solva Group. The boundary was considered to be sharp and unconformable by Jones (1940) but Stead and Williams (1971) considered it to be conformable and transitional. |
| Thickness: |
To 150m |
| Geographical Limits: |
Pembrokeshire. |
| Parent Unit: |
Caerfai Group (CIS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Foreshore and cliffs on both sides of Caerbwdy Bay. Cox et al., 1930. |
| Partial Type Section |
Quarry on west side of Caerbwdy Bay, 1.8km southeast of St David's. Basal part of sequence. Cox et al., 1930. |
| Reference(s): |
| Harkness, R and Hicks, H. 1871. On the ancient rocks of the St David's promontary, South Wales, and their fossil contents. Quarterly Jounrnal of the Geological Society of London, Vol.27, 384-404. |
| Jones, O T. 1940. Some Lower Palaeozoic contacts in Pembrokeshire. Geological Magazine, Vol.77, 405-409. |
| Williams, T G. 1934. The Precambrian and Lower Palaeozoic rocks of the eastern end of St David's Precambrian area Pembrokeshire. Quarterly Journal of the Geological Society, London, Vol.90, 32-75. |
| Rushton, A W A. 1974. The Cambrian of Wales and England, 43-121 in Holland, C H (editor), The Cambrian of the British Isles, Norden and Spitzbergen (Lower Palaeozoic rocks of the world, 2). [London: John Wiley and Son.] |
| Green, J F N. 1908. The geological structure of the Saint David's area (Pembrokeshire). Quarterly Journal of the Geological Society of London, Vol.64, 363-383. |
| Thomas, H H and Jones, O T, 1912. On the Pre-Cambrian and Cambrian rocks of Brawdy, Haycastle and Brimaston, (Pembrokeshire). Quarterly Journal of the Geological Society of London, Vol.68, 374-401. |
| Cox, A H, Green, J F N, Jones, O T, and Pringle, J. 1930. The Geology of the St David's district, Pembrokeshire. Proceedings of the Geologists' Association, Vol.41, 241-273. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E209
|
