The BGS Lexicon of Named Rock Units — Result Details

Carnedd Y Filiast Grit Member

Computer Code: CGR Preferred Map Code: CGr
Status Code: Full
Age range: Merioneth Series (EM) — Merioneth Series (EM)
Lithological Description: Coarse-grained massive quartzose and pebbly sandstones.
Definition of Lower Boundary: At base of sandstones forming top part of the Marchlyn Formation.
Definition of Upper Boundary: Unconformity at top of Marchlyn Formation.
Thickness: 30-60m
Geographical Limits: Northern Snowdonia.
Parent Unit: Marchlyn Formation (MAF)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Cwm Graianog. 
Reference(s):
Howells M F, Reedman A J and Leveridge B E. 1985. Geology of the country around Bangor: Explanation for 1:50 000 geological sheet 106 (England and Wales). British Geological Survey Sheet Explanation. [London: HMSO.] 34pp. 
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 E106