| Computer Code: |
LCV |
Preferred Map Code: |
LCV |
| Status Code: |
Full |
| Age range: |
Longvillian Substage (OL)
— Woolstonian Substage (OS) |
| Lithological Description: |
Acidic ash-flow tuffs interbedded with siltstone, mudstone, hyaloclastite and thin basaltic tuffs. |
| Definition of Lower Boundary: |
On Cwm Eigiau Formation sandstones. |
| Definition of Upper Boundary: |
Overlain by mudstones and siltstones at the base of the Middle Crafnant Volcanic Formation. |
| Thickness: |
To 100m |
| Geographical Limits: |
Widespread in eastern Snowdonia (see Sheet 106). |
| Parent Unit: |
Snowdon Volcanic Group (SV)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Capel Curig. |
| Reference Section |
(Basal contact). Cae-Mawr. |
| Reference(s): |
| Howells, M F, Leveridge, B E and Evans, C D R, 1973. Ordovician ash-flow tuffs in eastern Snowdonia. Report of the Institute of Geological Sciences, No.73/3. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E106
E120
|
