| Computer Code: |
ARO |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Rawtheyan Stage (OW)
— Hirnantian Age (OH) |
| Lithological Description: |
Weathered dark blue blocky mudstone, well cleaved homogeneous blue mudstone (slate), dark blue micaceous mudstones often sandy or gritty, weathered to a dull bronze. |
| Definition of Lower Boundary: |
Drawn at the base of the Red Vein Formation where blue mudstones with orange weathering rest conformably upon mottled mudstones of the Abercwmeiddaw Group. |
| Definition of Upper Boundary: |
Drawn at the conformable upward passage of the Narrow Vein Formation where well cleaved slate passes into a dark blue micaceous sandy and gritty mudstone of the Garwedd-Wen Formation. |
| Thickness: |
633 metres approx. |
| Geographical Limits: |
Exposed in the area around Corris and Aberllefenni, Merionethshire. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Abercorris, North of Corris, Merioneth. |
| Reference(s): |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
