The BGS Lexicon of Named Rock Units — Result Details

Luxton Nodular Limestone Formation

Computer Code: LNL Preferred Map Code: notEntered
Status Code: Full
Age range: Frasnian Age (DR) — Famennian Age (DA)
Lithological Description: Massive grey and red nodular limestones and nodular shales; grey and green micaceous shales with thick limestones; laminated and nodular limestones.
Definition of Lower Boundary: The lower boundary is an abrupt contact with either the East Ogwell Limestone (in the East Ogwell, Abbotskerswell and Denbury structural Units) or the Chercombe Bridge Limestone (in the Ugbrooke and Denbury Units). Where the lower boundary of the Luxton Nodular Limestone is with the Chercombe Bridge Limestone, the contact in the field would be noted by a change from the laminated and nodular limestone (described above in lithology section) to dark to medium grey well bedded fine-grained limestone with bed thicknesses of < 1.2 m with thin mudstone partings. In locations where the lower boundary is with the East Ogwell Limestone, the boundary will be marked by change from pale to medium grey or greyish pink poorly bedded limestone to laminated and nodular limestone (described above in lithology section).
Definition of Upper Boundary: The Luxton Nodular Limestone is overlain by the Whiteway Slate; the transition between this lithologies is marked by the change from nodular and laminated limestones of the Luxton Nodular Limestone to the predominance of grey-black, green and purple slates of the Whiteway Slates, which are locally calcareous and siliceous and rarely sideritic.
Thickness: Up to 150 m.
Geographical Limits: The Luxton Nodular Limestone is present in a cliff section on the northern side of the Teign Estuary ([SX 8962 7302] to [8969 7300], in the area around Well [SX 8776 7704] and in small exposures around Whiteway Barton [8820 7500]; all these localities are within south Devon.
Parent Unit: Not Applicable (-)
Previous Name(s): Luxton Nodular Limestone [Obsolete Name and Code: Use LNL] (-370)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  On the foreshore of the Teign Estuary, west of Luxton's Steps. Selwood et al., 1984. 
Reference(s):
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). 
Ussher, W A E. 1913. Geology of the country around Newton Abbot. Memoir of the British Geological Survey, Sheet 339. (England and Wales). 
House, M R and Butcher, N E, 1973. Excavations in the Devonian and Carboniferous Rocks near Chudleigh, south Devon. Transactions of the Royal Geological Society of Cornwall, Vol.20, p.199-220. 
House M R, and Butcher NE. 1962. Excavations in the Devonian and Carboniferous rocks of the Chudleigh area, south Devon. Proceedings of the Ussher Society, Vol 1, 28-29. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E339