| Computer Code: |
STYL |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Holkerian Substage (CQ)
— Asbian Substage (CR) |
| Lithological Description: |
Interbedded cryptalgal and fenestral, calcite mudstones, coquinoid limestones, skeletal, peloid, intraclast, ooid packstone/grainstones, ooid grainstones and the characteristic oncolitic grainstones. Scattered algal bioherms. Deposited in a peritidal enviroment. |
| Definition of Lower Boundary: |
Taken at the base of the first bed of calcite mudstone occuring above the ooid grainstones and the subordinate skeletal packstones of the underlying Cornelly Oolite Formation. |
| Definition of Upper Boundary: |
In the Vale of Glamorgan the top is taken at the sharp contact, defined by a paleokarstic surface, between the heterolithic lithologies of the Formation and the overlying partially dolomitised sandy skeletal packstones and calcareous sandstones of the Pant Mawr Sandstone Member [Oxwich Head Limestone Formation]. In Gower and Pembrokeshire it is taken at the palaeokarstic surface separating the heterolithic lithologies of the Formation from the mottled and pseudobrecciated skeletal packstones of the Oxwich Head Limestone Formation. |
| Thickness: |
55 to 65m in the central and western Vale of Glamorgan. |
| Geographical Limits: |
West and central Vale of Glamorgan [ST 00 74]. Present also in Gower [SS 50 90] and the Pembroke/Tenby [SM 99 01] area but has not been mapped. Passes laterally eastwards into the Hunts Bay Oolite Subgroup, that cannot be subdivided into Cornelly Oolite and Stormy Limestone formations. |
| Parent Unit: |
Hunts Bay Oolite Subgroup (HBO)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Stormy Down Quarry, 500m southeast of Ballas Farm, South Cornelly, Vale of Glamorgan. Lower third of unit exposed, comprising heterolithic peritidal limestones. Lower contact with underlying Cornally Oolite Formation seen; upper contact with Oxwich Head Limestone Formation not seen. |
| Reference(s): |
| Wilson, D, Davies, J R, Fletcher, C J N, and Smith, M. 1990. The Geology of the South Wales Coalfield, part VI the Country around Bridgend. Memoir of the British Geological Survey, 1:50 000 Geological Sheets 261 and 262 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E262
E261
|
