The BGS Lexicon of Named Rock Units — Result Details

Rhinog Formation

Computer Code: RN Preferred Map Code: RnS
Status Code: Full
Age range: Comley Series (EC) — Comley Series (EC)
Lithological Description: Grey to bluish grey, thick bedded turbiditic sandstones, conglomerates and laminated sandstones, with thin siltstone and mudstones intercalations.
Definition of Lower Boundary: Conformably overlies mudstones of the Llanbedr Formation, base being taken at the first pale green sandstone overlying the mudstones.
Definition of Upper Boundary: Conformable below siltstones of the Hafotty Formation.
Thickness: 400 to 780m
Geographical Limits: Harlech Dome.
Parent Unit: Harlech Grits Group (HGG)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Hell's Mouth Formation
Stratotypes:
Partial Type Section  Ffridd-Lwyd. Base and lower part of Formation. 
Reference(s):
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E135 E119 E149