| Computer Code: |
WWAT |
Preferred Map Code: |
Wwat |
| Status Code: |
Full |
| Age range: |
Frasnian Age (DR)
— Famennian Age (DA) |
| Lithological Description: |
Pale greenish-grey and buff, fine-grained, parallel bedded sandstones with minor mudstone interbeds. |
| Definition of Lower Boundary: |
Sharp, erosion surface cut in underlying Lower Devonian Brownstones or Upper Devonian Plateau Beds overlain locally in west by a fish-bearing basal conglomerate. [Lovell, 1978]. |
| Definition of Upper Boundary: |
Top of a persistent rubbly or massive calcrete, overlain by conglomerates of the Craig-y-cwm Formation. [Lovell, 1978]. |
| Thickness: |
About 8m in the Llangynidr area to about 16m in the Pontypool area, Gwent, South Wales. |
| Geographical Limits: |
From west of Llangynidr, Powys, eastwards and southwards to Pontypool, Gwent, South Wales. |
| Parent Unit: |
Portishead Subgroup (POB)
|
| Previous Name(s): |
Pale Quartzitic Sandstones [Obsolete Name and Code: Use WWAT]
(-3779)
|
| Alternative Name(s): |
Grey Grits [Obsolete: use GRG]
|
| Stratotypes: |
| Type Area |
Disused quarry near Wern Watkin Farm , near Llangynidr, Powys. Barclay, 1989. |
| Reference(s): |
| Barclay, W J, Jackson, D I, Mitchell, M, Owen, B, Riley, N J, White, D E, Strong, G E, and Monkhouse, R A. 1989. Geology of the South Wales Coalfield, Part II, the country around Abergavenny. Memoir of the British Geological Survey. |
| Lovell, R W W. 1978a. The sedimentology and stratigraphy of the Upper Old Red Sandstone and Lower Limestone Shales of the South Wales Coalfield. Unpublished PhD thesis, University of Bristol. |
| Barclay, W J. 1975. Annual report for 1974, p. 26. Institute for Geological Sciences: London. |
| Hall, I H S, Taylor, K, and Thomas, L P. 1973. The stratigraphy of the Upper Old Red Sandstone in south Breconshire. Bulletin of the Geological Survey of Great Britain, No. 44, 45-62. |
| Taylor, K, and Thomas, L P. 1974. Field meeting in the Upper Old Red Sandstone of south Breconshire. Proceedings of the Geologists' Association, Vol. 85, 423-432. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E232
|
