| Computer Code: |
CRDL |
Preferred Map Code: |
CRDL |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Massive limestone, with conglomeratic base resting on irregular surface of pillow lava. |
| Definition of Lower Boundary: |
Irregular unconformity on pillow lavas. The latter are possibly Balcreuchan Group (Arenig) but could be of much younger (Carodoc) age. |
| Definition of Upper Boundary: |
Not seen (faulted), but thought to be overlain by the Plantinhead Member of the Ardwell Farm Formation. |
| Thickness: |
To 90m |
| Geographical Limits: |
Area around the south and east side of Craighead Hill. Girvan, Ayrshire, Scotland. |
| Parent Unit: |
Ardwell Subgroup (AWL)
|
| Previous Name(s): |
Craighead Limestone [Obsolete Name and Code: Use CRDL]
(-3955)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Craighead Quarry, 6km northeast of Girvan, Ayrshire, Scotland. Williams, 1962. |
| Reference(s): |
| Fortey, R A, Harper, D A T, Ingham, J K, Owen, A W, Parkes, M A, Rushton, A W A and Woodcock, N H. 2000. A revised correlation of Ordovician rocks in the British Isles. Geological Society Special Report, No.24. |
| Williams, A, 1962. The Barr and Lower Ardmillan Series (Caradoc) of the Girvan district, southwest Ayrshire, with descriptions of the Brachiopoda. Memoir of the Geological Society of London, No.3. |
| Murchison, R I. 1851. On the Silurian rocks of the south of Scotland. Quarterly Journal of the Geological Society of London, Vol.7, p.137. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S014
|
