Chalk Group Lithostratigraphy: Northern England - Ferriby Formation
Wood & Smith (1978) included in the base of the Ferriby Chalk Formation red and pink-coloured ferruginous limestone, mostly belonging to the Albian and generally referred to as 'Red Chalk'. The latter was named the Hunstanton Member (Wood & Smith, 1978; Gaunt et al., 1992), but later described as a separate formation by Whitham (1991). The Ferriby Formation as used herein follows the restricted definition of Whitham (1991).
The Ferriby Formation (stratotype: Rugby Cement Co. Quarry, South Ferriby [SE 991 204]), typically c. 21-24 m thick (Wood & Smith, 1978; Gaunt et al., 1992), comprises flintless, marly, locally bioclastic and calcarenitic chalk. It is mostly dark to pale grey, sometimes bluish-grey coloured, but locally stained red or pink at some horizons, and some of the higher beds include hard, massive-bedded, cream-coloured chalk with thin marls (Wood & Smith, 1978; Gaunt et al., 1992, Whitham, 1991). The base of the formation is the erosion surface at the top of the underlying Hunstanton Formation, and the top is another erosion surface that underlies the Black Band. A number of key marker beds are recognised as follows:
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.
WHITHAM, F.1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. Proceedings of the Yorkshire Geological Society, Vol. 48(3), 227-255.
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: Black Band