The BGS Lexicon of Named Rock Units — Result Details

Penrhiw Group

Computer Code: PVP Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Proterozoic Eon (AP) — Proterozoic Eon (AP)
Lithological Description: Red and green trachytic and andesitic tuffs as well as halleflinta and porcellanites. Feldspathic grit with fragments of felsite and vesicular andesites.
Definition of Lower Boundary: Drawn at base of halleflinta of Penrhiw Group. (Base not seen). (Penrhiw Group = part of Pebidian Complex).
Definition of Upper Boundary: Drawn at conformable upward passage from feldspathic grit of the Penrhiw Group to green grit with trachyte fragments of the Treginnis Group.
Thickness: At least 310 metres.
Geographical Limits: South-west Wales.
Parent Unit: Pebidian Supergroup (PN)
Previous Name(s): Penrhiw Series (-4276)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Penrhiw Vicarage, St Davids, Dyfed, Wales. 
Reference(s):
Pringle, J and George, T N, 1948. South Wales. British Regional Geology. 
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. 
Harris, A L and others, 1973. A correlation of the Pre-Cambrian rocks in the British Isles. Geological Society of London Special Report No 6. 
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:
none recorded or not applicable