| Computer Code: |
SA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Oligocene Epoch (GO)
— Oligocene Epoch (GO) |
| Lithological Description: |
Grey and red mottled clay, white sandy clay and white, brown and red sands. The sands contain a range of minerals that indicate the sediments were derived locally; these include haematite, tourmaline, zircon, rutile, cyanite, andalusite, topaz and cassiterite. The beds also contain blocks of conglomerate containing rolled pebbles of quartz and cleaved mudstone. |
| Definition of Lower Boundary: |
Unconformable on the erosion surface of cleaved mudstones. |
| Definition of Upper Boundary: |
Present day erosion surface; locally covered by Head deposits of up to 1.2 m thickness. |
| Thickness: |
Variable; up to 5 m. |
| Geographical Limits: |
none recorded or not applicable
|
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
St Agnes Beds
|
| Stratotypes: |
| Type Area |
Around St Agnes' Beacon, north Cornwall coast. De la Beche, 1839. |
| Reference(s): |
| De La Beche, H T, 1839. Report on the geology of Cornwall, Devon and west Somerset. Memoir of the Geological Survey. |
| Reid, C, and Scrivenor, J B. 1906. The Geology of the country around Newquay. Memoirs of the Geological Survey, England and Wales. Explanation of sheet 346. |
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
