| Computer Code: |
HNCS |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Asbian Substage (CR)
— Asbian Substage (CR) |
| Lithological Description: |
Calcareous, locally conglomeratic, sandstone, with distinctive honeycomb weathering, locally in two tongues, separated by pale grey oolitic grainstone. Deposited as a transgressive shoreface sand/ooidal limestone. |
| Definition of Lower Boundary: |
Taken at sharp junction of the calcareous sandstone of the Member and the underlying dark bituminous skeletal/peloidal grainstone/packstone/wackestone of the Dowlais Limestone Formation. |
| Definition of Upper Boundary: |
Taken at the top of the upper tongue of calcareous sandstone of the Member, above which the pale grey ooid grainstones of the Penderyn Oolite Member enter. |
| Thickness: |
4 to 12m |
| Geographical Limits: |
Northwest crop of the South Wales Coalfield [SN 94 14]. |
| Parent Unit: |
Oxwich Head Limestone Formation (OHL)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Penderyn Quarry [Cwar Aberamman], 250m east of Penderyn Church, Penderyn, Powys. Entire unit seen, comprising, lower tongue of sandstone [1.2m], intervening crinoidal/ooidal limestones [2m] and upper tongue of sandstone [1.2m]. Contacts with underlying Dowlais Limestone Formation and overlying Penderyn Limestone Member exposed. |
| Reference(s): |
| Robertson, T. 1932. Geology of the South Wales Coalfield, Part V, the country around Merthyr Tydfil, 2nd edition. Memoir of the Geological Survey of Great Britain, Sheet 231. |
| Barclay, W J, Taylor, K, and Thomas, L P. 1988. Geology of the South Wales Coalfield. Part V. The country around Merthyr Tydfil. Third Edition. Memoir of the British Geological Survey, Sheet 231 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E231
|
