| Computer Code: |
CDRO |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Holkerian Substage (CQ)
— Holkerian Substage (CQ) |
| Lithological Description: |
Pale grey ooidal limestone. |
| Definition of Lower Boundary: |
Taken at the incoming of pale grey ooidal limestones of the Cheddar Oolite Member above the dark limetones of the Cheddar Limestone Member. |
| Definition of Upper Boundary: |
Taken at the incoming of dark grey fine-grained limestone, rich in corals, of the undivided Clifton Down Limestone Formation, above the pale ooidal limestone of the Cheddar Oolite Member. |
| Thickness: |
36 to 60m in the Cheddar area, south-central Mendip. |
| Geographical Limits: |
Chedder [ST 48 54] area, south-central Mendip. Passes laterally into the Clifton Down Limestone Formation in all directions. |
| Parent Unit: |
Clifton Down Limestone Formation (CDL)
|
| Previous Name(s): |
Cheddar Oolite Formation
(-761)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Chedder Gorge, Mendips, Somerset. Unit is 55m thick and most is exposed apart from a gap in the upper part. Comprises pale grey ooidal limestone. Lower contact with the Chedder Limestone Member and upper contact with the undivided Clifton Down Limestone Formation seen. See Green and Welch, 1965. |
| Reference(s): |
| Green, G W and Welch F B A, 1965. The geology of the country around Wells and Chedder. Memoir of the Geological Survey of England and Wales, Sheet 280. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E280
|
