The BGS Lexicon of Named Rock Units — Result Details

Dawlish Sandstone Formation

Computer Code: DAS Preferred Map Code: DaS
Status Code: Full
Age range: Permian Period (P) — Permian Period (P)
Lithological Description: Reddish brown sands and sandstones, cross-bedded, with intercalated thin lenses and beds of breccia and mudstone. North of Broadclyst, two mappable units predominantly of mudstone have been named: Poltimore Mudstone and Bussell's Member.
Definition of Lower Boundary: South of Exminster, interdigitational with Heavitree Breccia. From Exminster to Monkerton (SX 970 940), sharp base on Heavitree Breccia or Monkerton Formation. North of Monkerton to near Broadclyst, rests unconformably on Crackington Formation. In Crediton Trough, rests on Shute Sandstone.
Definition of Upper Boundary: Overlain sharply and probably unconformably by mudstones of the Aylesbeare Mudstone Group in the Exeter district; in the Newton Abbot district is overlain interdigitationally by the Exe Breccia.
Thickness: 100-300m.
Geographical Limits: Extends from Dawlish in south through Topsham to Broad Clyst as c.3km-wide outcrop. In Crediton Trough, present between Brampford Speke in west to near Budlake in the east.
Parent Unit: Exeter Group (EXE)
Previous Name(s): Clyst Sands [Obsolete Name And Code: See DAS] (CLYS)
Dawlish Sands (-838)
Dawlish Sandstones (-839)
Dawlish Sandstones And Breccias (-2739)
Lower Sandstone (-1475)
Dawlish Sandstone (-188)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Dawlish to near Langstone Rock (SX 980 780). Succession visible in cliffs west of railway. Aeolian and fluvial cross-bedded sandstones with some interbedded breccia. Grades up into Exe Breccia towards Langstone Rock. 
Reference(s):
Bristow, C R and Williams, B J, 1984. Geological Notes and Local Details for 1:10,000 Sheets. Sheet SX99SE (Pinhoe and Clyst St Mary, Devon). (Exeter: British Geological Survey). 
Laming, D J C, 1982. The New Red Sandstone. "In" Durrance, E M and Laming, D J C, (Editors). The Geology of Devon, p.148-177. 
Bristow, C R and Scrivener, R C, 1984. The stratigraphy and structure of the Lower New Red Sandstone of the Exeter district. Proceedings of the Ussher Society, Vol.6, p.68-74. 
Laming, D J C, 1966. Imbrication, palaeocurrents and other sedimentary features in the Lower New Red Sandstone, Devonshire. Journal of Sedimentary Petrology, Vol.36, p.940-959. 
Selwood, E B, Edwards, R A, Simpson, S, Chesher, J A, Hamblin, R J O, Henson, M R, Riddolls, B W and Waters, R A. 1984. Geology of the countryside around Newton Abbot. Memoir of the British Geological Survey, Sheet 339 (England and Wales). 
Smith, D B and 4 others, 1974. A correlation of Permian rocks in the British Isles. Journal of the Geological Society of London, Vol.130, 1-45. 
Ussher, W A E, 1899. Exeter 1:63360 Geological Map. 
Ussher, W A E, 1913. Geology of the country around Newton Abbot. Memoir of the British Geological Survey, Sheet 339. (England and Wales). 
Henson, M R, 1971. The Permo-Triassic rocks of south Devon. Unpublished PhD Thesis, University of Exeter. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E339