The BGS Lexicon of Named Rock Units — Result Details

Kellaways Formation

Computer Code: KLB Preferred Map Code: Kys
Status Code: Full
Age range: Callovian Age (JC) — Callovian Age (JC)
Lithological Description: Mudstone, grey, commonly silici-silty or silici-sandy, with (predominantly in the upper part) beds of generally calcareous siltstone and sandstone.
Definition of Lower Boundary: Generally sharp, conformable or non-sequential junction with bioclastic limestone of underlying Cornbrash Formation, overlain by grey mudstone, commonly a thin unit of shell-fragmental, more or less sandy mudstone occurs at base (where this is more strongly cemented it is included in the Cornbrash Formation).
Definition of Upper Boundary: Generally sharp but conformable junction between sandstone/siltstone in upper part of formation with mudstone of overlying Oxford Clay Formation; in expanding successions, (Wessex Basin), arbitrary boundary drawn at the top of the highest substantial sandstone or sandy mudstone, above which the succession is predominantly mudstone; in the Market Weighton area, sharp disconformable contact with chalky argillaceous sediments of the Chalk Group/Hunstanton Formation.
Thickness: 0 to perhaps (in south Dorset) 50m; typically c.20m in the Wessex Basin, and c.5 to 8m on the East Midlands Shelf.
Geographical Limits: Dorset coast (Weymouth area) to Malton area, Yorkshire (just north of the Market Weighton High). Extensive in onshore subcrop, though absent over the interior of the London Platform.
Parent Unit: Ancholme Group (AMG)
Previous Name(s): Kellaways Rock Plus Kellaways Clay (-4730)
Kellaways Formation Plus Cayton Clay Formation (-2266)
Kellaways Beds (-347)
Kellaways Beds Formation (-996)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  'Fault Corner', Grange Top Quarry, Ketton, Rutland. Fully exposed, 8.50m thick (Hudson and Clements, 2007, 258-259) 
Type Section  BGS Tytherton No.3 Borehole, 2.7km eastnortheast of Chippenham, Wiltshire. ST 97SW/2, 3.35 to 24.27m depth. Top of formation not seen. Cave and Cox, 1975. 
Type Area  Kellaways, near Chippenham, Wiltshire. 
Reference Section  BGS Walks Farm Borehole, 2.5km northnortheast of Heckington, near Sleaford, Lincolnshire. TF14 NE/18. 91.60 to 98.37m depth. Berridge et al., 1999 and manuscript log of borehole TF/4NE/18 in BGS Archive. 
Reference(s):
Hudson, J D and Clements, R G. 2007. The Middle Jurassic Succession at Ketton, Rutland. Proceedings of the Geologists' Association, Vol 118, 239-264. 
Gaunt, G D, Fletcher, T P and Wood, C J. 1992. Geology of the country around Kingston upon Hull and Brigg. Memoir of the British Geological Survey, sheets 80 and 89 (England and Wales). 172pp. 
Arkell W J, 1933. The Jurassic System in Great Britain [Oxford: Clarendon Press.] 
Smith, W. 1817. Strata identified by organized fossils, Part 3. [London.] 
Berridge, N G, Pattison, J, Samuel, M D A, Brandon, A, Howard, A S, Pharaoh, T C and Riley, N J. 1999. Geology of the Grantham district. Memoir of the British Geological Survey, sheet 127 (England and Wales). 
Cave, R and Cox, B M. 1975. The Kellaways Beds of the area between Chippenham and Malmesbury, Wiltshire. Bulletin of the Geological Survey of Great Britain, No.54, 41-46. 
Judd, J W. 1875. The geology of Rutland and parts of Lincoln, Leicester, Northampton, Huntingdon and Cambridge. Memoir of the Geological Survey of Great Britain (Old Series sheet 64). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E102 E114 E127 E159 E171 E172 E187 E188 E202 E203 E204 E217 E218 E219 E220 E236 E237 E253 E266 E268 E281 E327 E341 E342 E343 E064 E072 E080 E081 E089