| Computer Code: |
ACV |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Neoproterozoic Era (AZ)
— Neoproterozoic Era (AZ) |
| Lithological Description: |
Mainly quartz-rhyolites, possibly with tuffs, and some hornblende-andesite. |
| Definition of Lower Boundary: |
Drawn at the base of the Clogwyn Group where the base of quartz-rhyolites possibly with tuffs and some hornblende-andesite; base not seen. |
| Definition of Upper Boundary: |
Drawn at the conformable upward passage of the Clogwyn Group where rhyolites with some tuffs are conformably overlain by grits and feldspathic tuffs of the Tryfan Group. |
| Thickness: |
305 metres approx. |
| Geographical Limits: |
Clogwyn Melyn, near Nantlle, Caernarvonshire. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Clogwyn Melyn, near Nantlle, Caernarvonshire. |
| Reference(s): |
| Morris, T O and Fearnsides, W G, 1926. The stratigraphy and structure of the Cambrian Slate Belt of Nantlle, (Caernarvonshire). Quarterly Journal of the Geological Society of London, Vol.82, p.250-303. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
