| Computer Code: |
POB |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Famennian Age (DA)
— Famennian Age (DA) |
| Lithological Description: |
Red-green mudstones and marls, red siltstones and red-yellow, hard, fine-grained quartzose sandstones, with conglomerate locally. |
| Definition of Lower Boundary: |
Unconformable contact on the underlying Black Nore Sandstone (Brownstones Formation of South Wales) or on Silurian Volcanics. |
| Definition of Upper Boundary: |
Incoming of shales and thin limestones of the Lower Limestone Shale Formation which rest conformably on the Portishead Formation. |
| Thickness: |
300 m. |
| Geographical Limits: |
Bristol - Mendip area. Splits laterally into Tintern Sandstone and Quartzite Conglomerate in Forest of Dean. |
| Parent Unit: |
Brecon Beacons Group (BRBE)
|
| Previous Name(s): |
Quartz Conglomerate Group (South Wales)
(QCG)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Woodhill Bay, Portishead. Coast south of Portishead. |
| Type Section |
Left bank of River Avon, Abbot's Leigh, Bristol (Avon Gorge). |
| Reference(s): |
| Kellaway, G A and Welch, F B A. 1955. The Upper Old Red Sandstone and Lower Carboniferous rocks of the Bristol and the Mendips compared with those of Chepstow and the Forest of Dean. Bulletin of the Geological Survey of Great Britain, No.9, p.1-21. |
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. |
| Kellaway, G A and Welch, F B A. 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E280
E281
E264
E250
E251
E279
|
