The BGS Lexicon of Named Rock Units — Result Details

Aylesbeare Mudstone Group

Computer Code: AYB Preferred Map Code: Ayb
Status Code: Full
Age range: Early Triassic Epoch (TE) — Early Triassic Epoch (TE)
Lithological Description: The undivided Aylesbeare Mudstone Group consists of reddish-brown silty mudstone and clayey siltstone; clayey fine-grained sandstone occurs locally, and less commonly, clean, fine- to medium-grained sandstone.
Definition of Lower Boundary: Where undivided the Aylesbeare Mudstone rests on red-brown sandstone of the Dawlish Sandstone, possibly unconformably. See Clyst St Lawrence Formation and Exmouth Mudstone and Sandstone Formation for definition of base where those formations are present.
Definition of Upper Boundary: Overlain sharply by the Budleigh Salterton Pebble Beds.
Thickness: 530m on south coast (Selwood, et al, 1984); about 400m in Exeter district.
Geographical Limits: Extends from south Devon coast between Exmouth and Budleigh Salterton in a north-south trending belt to area west of the Quantocks (Sheet 295).
Parent Unit: New Red Sandstone Supergroup (NRS)
Previous Name(s): Aylesbeare Group (-1321)
Lower Marls (-663)
Aylesbeare Mudstone Formation (-3185)
Exmouth Beds (-3186)
Alternative Name(s): none recorded or not applicable
Type Section  Sea cliffs between Exmouth (SY 003 805) and Budleigh Salterton (SY 059 815). See Exmouth Mudstone and Sandstone Formation, and Littleham Mudstone Formation. 
Type Area  Named by Smith, et al, (1974) as the village of Aylesbeare, Devon 
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. 
Edwards, R A, Scrivener, R C, Barton, C M, Bristow, C R, Williams, B J, Goode, A J J, Cornwell, J D, Royles, C P, Self, S J, Warrington, G, Riley, N J, Turner, N, Jones, N S, Smith, S A, Marks, R J, Fortey, N J, Morton, R D, Strong, G E, Kemp, S J, Forster, A, Ault, L, Haslam, H W and Chesley, J T. 1999. Geology of the country around Exeter. Memoir of the British Geological Survey, Sheet 325 (England and Wales). 
Ussher, W A E, 1902. The Geology of the country around Exeter. Memoir of the Geological Survey of Great Britain, Sheet 325. (England and Wales). 
Edwards, R A, 1984. Geological notes and local details for 1:10 000 Sheet SY08NW, (Woodbury, Devon). British Geological Survey. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E310 E311 E326 E340 E341 E342 E343