| Sub-system; sub-period | Series epoch | Stage/age | Radiometric date (Ma)* |
|---|---|---|---|
| UPPER CARBONIFEROUS |
Stephanian | Stephanian C | - 300 - 303
|
| Stephanian B | |||
| Barruelian | |||
| Cantabrian | |||
| Westphalian | Westphilian D | ||
| Bolsovian (C) | |||
| Duckmantian (B) | |||
| Langsettian (A) | |||
| Namurian | Yeadonian | ||
| Marsdenian | |||
| Kinderscoutian | |||
| Alportian | |||
| LOWER CARBONIFEROUS |
Chokierian | ||
| Arnsbergian | |||
| Pendleian | |||
| Viséan | Brigantian | ||
| Asbian | |||
| Holkerian | |||
| Arundian | |||
| Tournaisian | Chadian | ||
| Courceyan |
* Ma = 10-6 (one million years)
The period of the major sediment deposition in the study area is shown in bold - in the Namurian epoch lasting c. 12 Ma (million years) from approximately 315 - 325Ma.