The BGS Lexicon of Named Rock Units — Result Details

Prenteg Sandstone Member

Computer Code: PSA Preferred Map Code: Ps
Status Code: Full
Age range: Soudleyan Substage (OY) — Longvillian Substage (OL)
Lithological Description: Fine- to coarse-grained, locally magnetitic sandstones with abundant sedimentary structures.
Definition of Lower Boundary: Conformably overlies ash-flow tuffs and subordinate sediments of the Capel Curig Volcanic Formation.
Definition of Upper Boundary: Sharply but conformably overlain by thinly interbedded siltstones and mudstones and siltstones of the undivided Cwm Eigiau Formation.
Thickness: 100 to 200m
Geographical Limits: Snowdonia, North Wales.
Parent Unit: Cwm Eigiau Formation (CEI)
Previous Name(s): Pren-Teg Grit (-1776)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Basal stratotype exposed in crags 160m northeast of Hendre Selar, north of Tremadog, North Wales. Howells, M F and Smith, M. 1997. 
Reference(s):
Howells, M F and Smith, M. 1997. Geology of the country around Snowdon. Memoir of the British Geological Survey, Sheet 119 (England and Wales). (London: The Stationery Office). 104pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E119