Computer Code: |
BTD |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Langsettian Substage (CA)
— Bolsovian Substage (CC) |
Lithological Description: |
[Obsolete: use PCM]
Grey and dark grey mudstones with subsidiary feldspathic sandstones, siltstones, seatearths (fireclays) and coal seams. |
Definition of Lower Boundary: |
At junction (conformable) with underlying Gwespyr Sandstone (Halkyn Formation). |
Definition of Upper Boundary: |
At junction (conformable, diachronous) with overlying Buckley Formation. |
Thickness: |
Up to c.400 metres. |
Geographical Limits: |
Flintshire Coalfield, North Wales. Possible extension to all the North Wales Coalfields. |
Parent Unit: |
none recorded or not applicable
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Bettisfield Colliery No.2 Shaft. |
Reference(s): |
none recorded or not applicable |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E108
|