The BGS Lexicon of Named Rock Units — Result Details

Scalby Formation

Computer Code: SCY Preferred Map Code: Scy
Status Code: Full
Age range: Bathonian Age (JN) — Bathonian Age (JN)
Lithological Description: The lower part of the formation (Moor Grit Member) is dominated in coastal exposures by grey, medium- to coarse-grained, sporadically pebbly, trough cross-bedded sandstone, with thin siltstone and mudstone beds; plant fragments and fossil wood casts are common. Inland, in the Hambleton Hills (Powell et al., 1992) this member is represented by grey to white, fine-grained, orthoquartzitic sandstone, with low-angle cross stratification and planar bedding. The uppermost Long Nab Member comprises laminated grey mudstones and siltstones with yellowish grey, fine- to medium-grained, planar bedded and cross-stratified sandstones. Plant fragments and rootlets are common in both members, together with sporadic thin coals and grey mudstone seatearths.
Definition of Lower Boundary: The lower boundary is disconformable or unconformable, at the abrupt upward transition from grey, shelly mudstone or shelly sandstone of the Scarborough Formation to grey, cross-bedded and planar laminated sandstone with sporadic plant fragments of the lower part of the Scalby Formation (Moor Grit Member) (Gowland and Riding, 1991; Nami and Leeder, 1978; Powell et al., 1992). The boundary is commonly a scoured, erosional surface.
Definition of Upper Boundary: The upper boundary is conformable or disconformable, at the boundary between siltstone, mudstone or cross-bedded sandstone with plant fragments of the Long Nab Member (Scalby Formation) and the Cornbrash Formation, which at Cayton Bay [TA 078 841], comprises red-brown, sandy, nodular, bioturbated limestone with oysters and other bivalves; u-shaped burrows extend down from the base of the Cornbrash Formation into the underlying grey siltstone and silty sandstone of the Scalby Formation (Wright, 1977). Inland in the Hambleton Hills and Howardian Hills, the Cornbrash Formation (limestone) is generally absent (Powell et al., 1992, p.53) and the upper boundary is taken at the base of the yellow-brown, calcareous medium-grained sandstone with bivalves (Kellaways Rock Member, Osgodby Formation). The Kellaways Rock Member is referred to as the Redcliff Rock Member by Page (1989).
Thickness: Up to 60m on the North Yorkshire coast; 32 to 48m in the Hambleton Hills in the west of the outcrop.
Geographical Limits: North Yorkshire Moors, Cleveland Hills, Hambleton Hills and Howardian Hills, and is well exposed in several coastal cliff sections (Scalby Cliff) between Long Nab [TA 028 943] and Scalby Ness [TA 037 907], and south of Scarborough between South Bay [TA 046 875] and White Nab [TA 058 864] (Black, 1929; Hemingway and Knox, 1973; Nami and Leeder, 1978). Equivalent strata in Humberside and Lincolnshire are represented by the Redbourne Group (Gaunt et al., 1992). Offshore, the formation is equivalent, in part, to the Hudleston Formation of the West Sole Group (Lott and Knox, 1994).
Parent Unit: Ravenscar Group (RAG)
Alternative Name(s): none recorded or not applicable
Type Section  Coastal cliff section (Scalby Cliff) near Scalby Mills, north of Scarborough, between Long Nab [TA 028 943], Scalby Ness [TA 037 907] and southwards to Castle Hill [TA 048 893]. 
Reference Section  Reference section for the upper boundary on the south side of Cayton Bay, south of Scarborough. 
Fox-Strangways, C, Cameron, A G and Barrow, G. 1886. The geology of the country around Northallerton and Thirsk. Memoir of the Geological Survey of England and Wales 
Powell, J H, Cooper, A H and Benfield, A C. 1992. Geology of the country around Thirsk. Memoir of the British Geological Survey, Sheet 52 (England and Wales). 
Cope, J C W, Duff, K L, Parsons, C F, Torrens, H S, Wimbledon, W A and Wright, J K. 1980. A correlation of Jurassic rocks in the British Isles. Part 2: Middle and Upper Jurassic. Geological Society of London Special Report, 15, 73pp. 
Lott, G K and Knox, R W O'B. 1994. 7. Post-Triassic of the Southern North Sea. In: Knox, R W O'B and Cordey, W G (eds.), Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. 
Hemingway, J E. 1974. Jurassic. 161-233 in Rayner, D H and Hemingway, J E (eds.) The geology and mineral resources of Yorkshire. (Leeds: Yorkshire Geological Society.) 
Butler, N, Charnock, M A, Hager, K O and Watkins, C A. 2005. The Ravenscar Group: a coeval analogue for the Middle Jurassic reservoirs of the North Sea and offshore Mid-Norway. 43-53 in Powell, A J and Riding, J B (eds.), Recent Developments in Applied Biostratigraphy. The Micropalaeontological Society, Special Publications. 
Riding, J B and Wright, J K. 1989. Palynostratigraphy of the Scalby Formation (Middle Jurassic) of the Cleveland Basin, north-east Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.47, 349-354. 
Hancock, N J and Fisher, M J. 1981. Middle Jurassic North Sea deltas with particular reference to Yorkshire. 186-195 in Illing, L V and Hobson, G D (eds.), Petroleum geology of the continental shelf of north-west Europe. (London: Institute of Petroleum.) 
Fisher, M J and Hancock, N J. 1985. The Scalby Formation (Middle Jurassic, Ravenscar Group) of Yorkshire: reassessment of age and depositional environment. Proceedings of the Yorkshire Geological Society, Vol.45, 293-298. 
Fox-Strangways, C. 1892. Jurassic rocks of Britain, Vols 1 and 2, Yorkshire. Memoir of the Geological Survey of Great Britain. 
Nami, M and Leeder, M R. 1978. Changing channel morphology and magnitude in the Scalby Formation (M. Jurassic) of Yorkshire, England. In: Miall, A D (Ed.), Fluvial sedimentology. Memoir of the Canadian Society of Petroleum Geologists, No.5. 
Leeder, M R and Nami, M. 1979. Sedimentary models for the non-marine Scalby Formation (Middle Jurassic) and the evidence for late Bajocian/Bathonian uplift of the Yorkshire Basin. Proceedings of the Yorkshire Geological Society, Vol.42, 461-482. 
Richards, P C, Lott, G K, Johnson, H, Knox, R W O'B and Riding, J B. 1993. Jurassic of the Central and Northern North Sea. In: Knox, R. W. O'B. and Cordey, W. G. (eds), Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham, viii + 219 p. 
Knox, R W O'B, Howard, A S, Powell, J H and van Buchem, F S P. 1991. Lower and Middle Jurassic sediments of the Cleveland Basin N.E. England: Shallow marine and paralic facies seen in their sequence stratigraphic context. Field Excursion Guide, No.5; 13th International Sedimentological Congress, Nottingham, UK. 1990. 66pp. 
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. 
Livera, S E and Leeder, M R. 1981. The Middle Jurassic Ravenscar Group (Deltaic Series) of Yorkshire: recent sedimentological studies as demonstrated during a field meeting 2/3 May, 1980. Proceedings of the Geologists' Association, Vol.92, 241-250. 
Hemingway, J E and Knox, R W O'B. 1973. Lithostratigraphical nomenclature of the Middle Jurassic strata of the Yorkshire Basin of north-east England. Proceedings of the Yorkshire Geological Society, Vol.39, 527-535. 
Gowland, S and Riding, J B. 1991. Stratigraphy, sedimentology and palaeontology of the Scarborough Formation (Middle Jurassic) at Hundale Point, North Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.48, 375-392. 
Black, M. 1929. Drifted plant-beds of the Upper Estuarine Series of Yorkshire. Quarterly Journal of the Geological Society London, Vol.85, 389-437. 
Page, K N. 1989. A stratigraphical revision for the English Lower Callovian. Proceedings of the Geologists' Association, Vol.100, 363-382. 
Wright, J K. 1977. The Cornbrash Formation (Callovian) in North Yorkshire and Cleveland. Proceedings of the Yorkshire Geological Society, Vol.41, 325-346. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E033 E034 E035 E042 E043 E044 E052 E053 E063