| Computer Code: |
UAV |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
[Obsolete: use CGU, CYLF] Rhyolitic and acid-keratophyric lavas and tuffs with sporadic slates. (Correlative of Upper Acid Volcanic Group = Craig-y-Llam Group). |
| Definition of Lower Boundary: |
Drawn at base of lavas and tuffs of Upper Acid Volcanic Group where they rest conformably on the Llyn Cau Mudstones Group of Llandeilo age. |
| Definition of Upper Boundary: |
Drawn at conformable upward passage from ash beds of the Upper Acid Volcanic Group to the Talyllyn Mudstones of Caradoc age. |
| Thickness: |
Approx. 270-450 metres. |
| Geographical Limits: |
Mid-Wales. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
Craig-Y-Llam Group [Obsolete Name And Code: See CYLF]
(CYLL)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Craig-y-Llam, east of Cader Idris, Gwynedd. |
| Reference(s): |
| Pugh, W J. 1928. The geology of the district around Dinas Mawddwy (Merioneth). Quarterly Journal of the Geological Society of London. Vol.84, 345-381. |
| 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. 1925. The geology of the Cadair Idris Range, (Merioneth). Quarterly Journal of the Geological Society of London, Vol. 81, 539-592. |
| Wells, A K. 1925. The geology of the Rhobell Fawr district (Merioneth). Quarterly Journal of the Geological Society of London, Vol.81, 463-538. |
| Pugh, W J. 1923. The geology of the district around Corris and Aberllefenni, (Merionethshire). Quarterly Journal of the Geological Society, London, Vol.79, 508-541. |
| Cox, A H, and Wells, A K. 1927. The geology of the Dolgelley district, Merionethshire. Proceedings of the Geologists' Association, Vol. 38, 265-318. |
| Pugh, W J, 1929. The geology of the district between Llanymawddwy and Llanuwchllyn (Merioneth). Quarterly Journal of the Geological Society, Vol.85, p.248. |
| Davies, R G. 1959. The Cader Idris Granophyre and its associated rocks. Quarterly Journal of the Geological Society, London, Vol. 115, 189-216. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
