The BGS Lexicon of Named Rock Units — Result Details

Mynydd-Y-Gader Rhyolitic Group [See Lower Acid Volcanic Group]

Computer Code: MGV Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Arenig Series (OR) — Abereiddian Stage (O2)
Lithological Description: Rhyolitic lavas and pyroclastic rocks.
Definition of Lower Boundary: Drawn at the base of the Lower Ashes Formation where it rests conformably upon basement beds of Arenig age.
Definition of Upper Boundary: Drawn at the conformable upward passage of the China Stone Ashes Formation to the Moelyn Slates Formation of Llanvian age.
Thickness: Not known.
Geographical Limits: Dolgelly, North Wales.
Parent Unit: Not Entered (?)
Previous Name(s): Mynydd-Y-Gader Group (-1064)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Cader Idris, Gwynedd, North Wales. 
Reference(s):
Cox, A H and Wells, A K, 1916. The Ordovician sequence in the Cader Idris district (Merioneth). British Association for the Advancement of Science Report for 1915 (Manchester), p.424. 
Cox, A H and Wells, A K, 1927. The geology of the Dolgelley district, Merionethshire. Proceedings of the Geologists' Association, Vol.38, 265-318. 
Jones, B, 1933. The geology of the Fairbourne-Llwyngwril district, Merioneth. Quarterly Journal of the Geological Society, Vol.89, 145-171. 
Cox, A H, and Wells, A K, 1921. The Lower Palaeozoic rocks of the Arthog-Dolgellau district (Merionethshire). Quarterly Journal of the Geological Society, London, Vol.76, p. 254-324. 
Cox, A H. 1925. The geology of the Cadair Idris Range, (Merioneth). Quarterly Journal of the Geological Society of London, Vol.81, p.539-592. 
Davies, R G, 1959. The Cader Idris Granophyre and its associated rocks. Quarterly Journal of the Geological Society, London. Vol.115, 189-216. 
Wells, A K. 1925. The geology of the Rhobell Fawr district (Merioneth). Quarterly Journal of the Geological Society of London, Vol.81, 463-538. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable