| 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. |
| Stratotypes: |
| Type Section |
BGS Tytherton No.3 Borehole, 2.7km eastnortheast of Chippenham, Wiltshire. |
| Type Area |
Kellaways, near Chippenham, Wiltshire. |
| Reference Section |
'Fault Corner', Grange Top Quarry, Ketton, Rutland. |
| Reference Section |
BGS Walks Farm Borehole, 2.5km northnortheast of Heckington, near Sleaford, Lincolnshire. |
| Reference(s): |
| 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). |
| Gaunt, G D, Fletcher, T P amd 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). |
| 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. |
| 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). |
| Arkell, W J. 1933. The Jurassic System in Great Britain. [Oxford: Clarendon Press.] |
| Hudson, J D and Clements, R G. 2007. The Middle Jurassic succession at Ketton, Rutland. Proceedings of the Geologists' Association, Vol. 118, 239-264. |
