| Computer Code: |
MGV |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arenig Series (OR)
— Abereiddian Stage (O2) |
| Lithological Description: |
[Obsolete: use LAV]
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: |
none recorded or not applicable
|
| Previous Name(s): |
Mynydd-Y-Gader Group [Obsolete Name and Code: Use MGV, OF]
(-1064)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Cader Idris, Gwynedd, North Wales. |
| Reference(s): |
| Jones, B, 1933. The geology of the Fairbourne-Llwyngwril district, Merioneth. Quarterly Journal of the Geological Society, Vol.89, 145-171. |
| 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. |
| 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. |
| Cox, A H, and Wells, A K. 1927. The geology of the Dolgelley district, Merionethshire. Proceedings of the Geologists' Association, Vol.38, 265-318. |
| 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. 1921. The Lower Palaeozoic rocks of the Arthog-Dolgellau district (Merionethshire). Quarterly Journal of the Geological Society, London, Vol.76, p. 254-324. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
