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
Stratotypes:
Reference Section  Sandford. 
Type Area  Named from village of Knowle, near Crediton Devon. 
Reference Section  North of West Sandford. 
Reference Section  South of Brandirons Corner. 
Reference(s):
Hutchins, P F, 1963. The Lower New Red Sandstone of the Crediton Valley. Geological Magazine, Vol.100, 107-128. 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E324 E325 E339