The BGS Lexicon of Named Rock Units — Result Details

Wern Watkin Formation

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: Quartz Conglomerate Group (South Wales) (QCG)
Previous Name(s): Pale Quartzitic Sandstones (-3779)
Alternative Name(s): Equates With The Grey Grits Of The Merthyr Tydfil District.
Stratotypes:
Type Area  Disused quarry near Wern Watkin Farm , near Llangynidr, Powys. Barclay, 1989. 
Reference(s):
Lovell, R W W. 1978. 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 Unpublished PhD thesis, University of Bristol.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, p. 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. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E232