The BGS Lexicon of Named Rock Units — Result Details

Knowle Sandstone Formation

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 (-1003)
Alternative Name(s): none recorded or not applicable
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. 
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