| Computer Code: |
MCG |
Preferred Map Code: |
MCG |
| Status Code: |
Full |
| Age range: |
Oxfordian Age (JO)
— Oxfordian Age (JO) |
| Lithological Description: |
Sandstone, fine-grained, bedded, clayey in lower part passing calcareous and shelly upwards with scattered ooids, generally poorly fossiliferous; locally a sandy ooidal limestone with trigoniid bivalves, gastropods and ammonites is developed at the top (Newbridge Trigonia Bed; Coe, 1995, p. 169). |
| Definition of Lower Boundary: |
Conformable: sharp change upwards into calcareous fine-grained sandstone from sandy ooidal limestone (Hambleton Oolite Member). Where this is absent, difficult to distinguish from Birdsall Calcareous Grit Member. |
| Definition of Upper Boundary: |
Conformable or non-sequence: sharp change up from calcareous fine-grained sandstone or locally a sandy ooidal limestone (Newbridge Trigonia Bed) into generally non-sandy ooidal limestone (Malton Oolite Member), at the base of a black ooid-limestone bed at Newbridge Quarry (Coe, 1995). |
| Thickness: |
12 to 15m in the Tabular Hills thinning to zero south of Malton and near Scarborough, less than 2m at Spiker's Hill Quarry. |
| Geographical Limits: |
Central and western Cleveland Basin, North Yorkshire, overstepped eastwards by Malton Oolite Member. |
| Parent Unit: |
Coralline Oolite Formation (COO)
|
| Previous Name(s): |
Middle Calcareous Grit [Obsolete Name and Code: Use MCG]
(-4183)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Spikers Hill Quarry, West Ayton, North Yorkshire. Exposes entire member, 1.17m thick, comprising bedded clayey fine-grained sandstone, underlain by Hambleton Oolite Member, non-sequentially overlain by Malton Oolite Member. Type Section proposed here; Wright, 1972, p.237; Wright and Cox, 2001, pp 157-161. |
| Reference Section |
Newbridge Quarry, Pickering, North Yorkshire. Exposes upper part of member, about 2.3m thick, comprising siltstone, overlain by sandy, shelly ooidal limestone and ooidal fine-grained sandstone (Newbridge Trigonia Bed), overlain by Malton Oolite Member. Nearby [SE 8017 8565], the lower part, bioturbated fine-grained sandstone beds are exposed. Coe, 1995 |
| Type Section |
Love Lane Quarry, Pickering, North Yorkshire. 5m of massive, calcareous sandstone is currently seen with the Newbridge Trigonia Bed clearly visible near the top, with a conformable upward transition into the Malton Oolite Member. Formerly exposed up to 8.5m of strata but base not seen. Blake and Hudleston, 1877, pp 334-336; Arkell, 1933, pp 426-427. |
| Reference(s): |
| Coe, A L. 1995. A comparison of the Oxfordian successions of Dorset, Oxfordshire and Yorkshire. 151-172 in Taylor, P D (Ed.) Field Geology of the British Jurassic. [Bath: The Geological Society.] |
| Wright, J K. 1972. The stratigraphy of the Yorkshire Corallian. Proceedings of the Yorkshire Geological Society, Vol. 39, 225-266. |
| Blake, J F, and Huddleston, W H. 1877. On the Corallian rocks of England. Quarterly Journal of the Geological Society of London, Vol. 33, 260-405. |
| Arkell, W J. 1933. The Jurassic System in Great Britain (Oxford: Clarendon Press.) |
| Wright, J K, and Cox, B M. 2001. British Upper Jurassic Stratigraphy (Oxfordian to Kimmeridgian). Geological Conservation Review Series. No. 21. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) |
| Rawson, P F and Wright, J K. 1995. Jurassic of the Cleveland Basin, North Yorkshire. 173-208 in Taylor, P D (Ed.) Field Geology of the British Jurassic. (London: Geological Society.) |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E043
E044
E052
E053
E054
|
