| Computer Code: |
ACC |
Preferred Map Code: |
AcC |
| Status Code: |
Full |
| Age range: |
Rhuddanian Age (SR)
— Rhuddanian Age (SR) |
| Lithological Description: |
Conglomerates, pebbly mudstones and sandstones. A few thin mudstone beds. |
| Definition of Lower Boundary: |
Sharp and erosional. Taken at base of first bed of pebbly mudstone or conglomerate above the Tycwtta Mudstones or Yr Allt Formation. |
| Definition of Upper Boundary: |
Gradational but taken at base of first thick mudstone unit of overlying Pistyll Gwyn Mudstones. |
| Thickness: |
12 - 80 metres. |
| Geographical Limits: |
Central Wales, east of Tywi Anticline. |
| Parent Unit: |
Not Available (!)
|
| Previous Name(s): |
Allt-Y-Clych Conglomerate Member (Form Facies) [Obsolete Name and Code: Use ACC]
(-1298)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Prominent line of crags running north-east/south-west through the summit of Ally-Y-Clych, Llanafan-Fawr. |
| Reference(s): |
| Lockley, M G. 1978. New Evidence on the age of some Lower Palaeozoic rocks near Llanafan-Fawr. Geological Journal, Vol.13, 15-24. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E179
|
