The BGS Lexicon of Named Rock Units — Result Details

Monkerton Formation

Computer Code: MKN Preferred Map Code: Mkn
Status Code: Full
Age range: Permian Period (P) — Permian Period (P)
Lithological Description: Clayey fine-grained sandstone (locally medium- or coarse-grained); sandstone, sandy mudstone, silty mudstone, thin breccia beds. The formation passes laterally and downwards into the Heavitree Breccia.
Definition of Lower Boundary: Overlies thin sequence of Heavitree Breccia in Hill Barton [SX 956 928], Exeter, with fairly sharp upward passage from breccia into a mainly clayey sequence. Around [SX 965 940], the Monkerton Formation rests directly on Whipton Formation.
Definition of Upper Boundary: Overlain by Dawlish Sandstone: the passage from clayey silty sandstones of the Monkerton Formation takes place within about 1m of strata.
Thickness: To 40m
Geographical Limits: Small area northeast of Exeter, Devon, from Hill Barton [SX 956 928] in the west, through Monkerton [SX 965 938], to just beyond the M5 Motorway in the east [SX 974 939].
Parent Unit: Exeter Group (EXE)
Previous Name(s): Monkerton Member (-4797)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Monkerton area of Exeter, Devon. Few exposures; outcrop mainly determined by augering. No suitable type section. Small exposures (eg SX 9538 9355, SX 9540 9353) in Hospital Lane reveal sandstone, clayey sandstone and clayey breccia. 
Reference(s):
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. 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable