| Computer Code: |
KNS |
Preferred Map Code: |
KnS |
| Status Code: |
Full |
| Age range: |
Permian Period (P)
— Permian Period (P) |
| Lithological Description: |
Reddish brown sandstone, mostly well cemented, with common breccia beds and lenses, commonly cross-bedded. Contains interbedded lamprophyre and basalt lavas. |
| Definition of Lower Boundary: |
On northern side of the Crediton Trough, Bow Breccia with passes up into Knowle Sandstone by gradual increase in the proportion of sandstone; thus the boundary is somewhat arbitrary. Around Posbury and in the Dunchideock area (southwest of Exeter), rests directly on Crackington Formation. |
| Definition of Upper Boundary: |
Overlain unconformably by Creedy Park Sandstone along north side of Crediton Trough. At Posbury and Dunchideock, overlain by basalt, in turn overlain by Crediton or Alphington Breccia. |
| Thickness: |
120-150m at eastern edge of Okehampton district, to 100m in Crediton area, 18m at Bow. |
| Geographical Limits: |
Present in Okehampton district from south of Bow to Knowle; and in Exeter district from Knowle to Sandford area. (All within Crediton Trough). |
| Parent Unit: |
Exeter Group (EXE)
|
| Previous Name(s): |
Knowle Sandstones [Obsolete Name and Code: Use KNS]
(-1003)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
North of West Sandford. |
| Reference Section |
Sandford. |
| Type Area |
Named from village of Knowle, near Crediton Devon. |
| Reference Section |
South of Brandirons Corner. |
| Reference(s): |
| Edmonds, E A, Wright, J E, Beer, K E, Hawkes, J R, Fenning, P J, Freshney, E C, Lovelock, P E R, McKeown, M C, Ramsbottom, W H C, and Williams, M. 1968. Geology of the country around Okehampton. Memoir of the Geological Survey of Great Britain, Sheet 324 (England and Wales). |
| Hutchins, P F, 1963. The Lower New Red Sandstone of the Crediton Valley. Geological Magazine, Vol.100, 107-128. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E324
E325
E339
|
