| Computer Code: |
HFM |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Frasnian Age (DR)
— Famennian Age (DA) |
| Lithological Description: |
A limestone shale facies comprising a dark grey marine shale sequence. A grit and sandstone facies comprising pale whitish grey fine-grained sandstone and a calcareous sandstone shale facies comprising alternating thinly bedded dark grey fine-grained silty sand with fragmental limestone. |
| Definition of Lower Boundary: |
Drawn at the base of the calcareous sandstone shale facies where it rests conformably upon the lagoonal red beds of the Hopcroft Hall Group. |
| Definition of Upper Boundary: |
Drawn at the unconformity between the limestone shale facies of the Holt Farm Group with the overlying basalt igneous intrusion. |
| Thickness: |
65m approx. |
| Geographical Limits: |
Steeple Aston, Oxfordshire. |
| Parent Unit: |
Old Red Sandstone Supergroup (ORS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Steeple Aston, Oxfordshire. |
| Reference(s): |
| Poole, E G. 1977. Stratigraphy of the Steeple Aston Borehole, Oxfordshire. Bulletin of the Geological Survey of Great Britain, Vol. 57, 1-85. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
