Chalk Group Lithostratigraphy: Northern England - North Ormsby Marl
This is a laminated marl, up to 110mm thick, with a sharp base and gradational top (Wood & Smith, 1978), equating with the Grimes Graves Marl of the East Anglia Chalk Group succession and the Bridgewick Marl 1 of the Lewes Nodular Chalk Member in southern England (Mortimore & Wood, 1986). In Germany the probable correlative of the North Ormsby Marl is a similarly thick marl designated ME (Gaunt et al., 1992) In conjunction with the underlying Ravendale Flint and Triple Tabular Flint, and overlying Ludborough Flint, it forms a mappable feature that equates with the Brandon Flint Series of East Anglia and the Basal Complex of the North Downs (Gaunt et al., 1992).
Macrofossil Biozonation: S. plana Zone
Correlation: see Correlation with other UK Chalk Group successions
References
GAUNT, G D, FLETCHER, T P & WOOD, C J. 1992. Geology of the country around Kingston-upon-Hull and Brigg. Memoir of the British Geological Survey.
MORTIMORE, R N & WOOD, C J.1986. The distribution of flint in the English Chalk, with particular reference to the 'Brandon Flint Series' and the high Turonian flint maximum. In SIEVEKING, G de C & HART, M B. The scientific study of flint and chert. Cambridge University Press, Cambridge.
WOOD C J & SMITH, E G.1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. Proceedings of the Yorkshire Geological Society, Vol. 42(2), 263-287.
See: Brandon Flint Series, Basal Complex