The BGS Lexicon of Named Rock Units — Result Details

Barmouth Formation

Computer Code: BAG Preferred Map Code: BaGS
Status Code: Full
Age range: St David's Series (ED) — St David's Series (ED)
Lithological Description: Coarse grained turbiditic sandstone and subordinate mudstone.
Definition of Lower Boundary: Conformable on siltstones and mudstones of the Hafotty Formation.
Definition of Upper Boundary: Sharply and conformable overlain by silty mudstone of the Gamlan Formation.
Thickness: 60-230m
Geographical Limits: Harlech Dome.
Parent Unit: Harlech Grits Group (HGG)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Above Barmouth, North Wales. See Allan and Jackson, 1985. 
Reference(s):
Crimes, T P. 1970. A facies analysis of the Cambrian of Wales. Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.7, 113-170. 
Allen, P M and Jackson, A A. 1985. Geology of the country around Harlech. Memoir of the British Geological Survey, Sheet 135 with part of Sheet 149 [England and Wales]. [London: HMSO.] 112pp. 
Matley, C A and Wilson, T S. 1946. The Harlech Dome, North of the Barmouth Estuary. Quarterly Journal of the Geological Society of London, Vol.102, 1-40. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E119 E135 E149