| Computer Code: |
GWT |
Preferred Map Code: |
notEntered |
| Status Code: |
Pending Upgrade |
| Age range: |
Costonian Substage (OO)
— Costonian Substage (OO) |
| Lithological Description: |
Lapilli-crystal tuff with varying amounts of epiclastic material. |
| Definition of Lower Boundary: |
Conformably overlies mudstones of the Llangynog Formation. |
| Definition of Upper Boundary: |
Conformably overlain by volcaniclastic mudstones of the Llangynog Formation. |
| Thickness: |
5 to 6m |
| Geographical Limits: |
No data. |
| Parent Unit: |
Llangynog Formation (LGF)
|
| Previous Name(s): |
Garwallt Ash [Obsolete Name and Code: Use GWT]
(-3450)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| none recorded or not applicable |
| Reference(s): |
| Wedd, C B, Smith, B, King, W B R and Wray, D A. 1929. Geology of the country around Oswestry. Memoir of the Geological Survey of Great Britain, Sheet 137. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E137
|
