| Computer Code: |
CWMF |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Ludlow Epoch (SU)
— Pridoli Epoch (SO) |
| Lithological Description: |
Mainly calcretised green siltstones, green and pale grey sandstones, some of which are conglomeratic and pebbly, and calcrete-clast intraformational conglomerates.
Fluvial sheetflood and channelised sands with floodplain silts subjected to subaerial exposure and carbonate soil formation.
Probably late Ludlow to Pridoli. |
| Definition of Lower Boundary: |
The lower boundary is an unconformity overstepping progressively on to lower rocks westwards from the Cennen Valley to rest on Ordovician strata. |
| Definition of Upper Boundary: |
The upper boundary is conformable with green calcretised mudstones that were formerly considered to comprise the same lithostratigraphical unit (the Green Beds), but are now recognised as typical Temeside Mudstone Formation lithologies, as for example in Nant Cwmffrwd [SN 423 173]. |
| Thickness: |
Up to 65 m. |
| Geographical Limits: |
West of the Cennen Valley, Carmarthenshire. |
| Parent Unit: |
Milford Haven Subgroup (MIH)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Nant Cwmfffrwd [SN 423 173] provides a well exposed type section, where the base is unconformable on strata of Arenig age. |
| Reference(s): |
| Barclay, W J, Davies, J R, Hillier, R D, and Waters, R A. 2015. Lithostratigraphy of the Old Red Sandstone successions of the Anglo-Welsh Basin. British Geological Survey Research Report, RR/14/02. 96pp. |
| Strahan, A. 1907. The geology of the South Wales Coalfield, Part VIII. The country around Swansea. Memoir of the Geological Survey. England and Wales. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
