| Computer Code: |
CNG |
Preferred Map Code: |
notEntered |
| Status Code: |
Index Level |
| Age range: |
Llandovery Epoch (SL)
— Llandovery Epoch (SL) |
| Lithological Description: |
[Obsolete] Thickly bedded conglomerates, grits, flags and shales. |
| Definition of Lower Boundary: |
Drawn at the base of Caban Conglomerate Formation where thickly bedded dark grey quartzose grits and conglomerates conformably rest upon mudstone of the Gigrin Mudstones Formation. |
| Definition of Upper Boundary: |
Drawn at the conformable upward passage of the Gaffallt Member where it is unconformably overlain by pale green, blue and grey shales and mudstones of the Rhayader Pale Shales. |
| Thickness: |
304 metres. |
| Geographical Limits: |
The area around Rhayader, Radnorshire and Breconshire. |
| 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 Area |
Caban Coch Gorge and Cnwch Hill, 6kms to 8kms south west of Rhayader, Radnorshire and Breconshire. |
| Reference(s): |
| Neville, G T, 1970. British Regional Geology, South Wales (Third Edition). |
| Lapworth, H, 1900. The Silurian sequence at Rhayader. Quarterly Journal of the Geological Society, Vol.56, p.67-137. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
