South-west England Chalk Group Lithostratigraphy: Jarvis & Woodroof (1984) & Jarvis & Tocher (1987) - Seaton Chalk Formation

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The Seaton Chalk Formation (stratotype: Whitecliff [SY 233 893], Devon), c. 36.5 m thick at Whitecliff (Woods, ####), comprises hard, yellow-stained nodular chalk with hardgrounds and sparse flints in the lower part, named the Connett's Hole Nodular Chalk Member, and soft, white, smooth-textured chalk, with abundant small, spikey flints and bands of marly chalk in the upper part, named the Beer Roads Flinty Chalk Member (Jarvis & Woodroof, 1984). The base of the formation is immediately above the top of the Haven Cliff Neocardioceras Hardground, which marks the top of the underlying Beer Head Limestone Formation (Jarvis & Woodroof, 1984). The lowest development of conspicuously nodular chalk that characterises the overlying St Margarets Chalk member marks the top of the Seaton Chalk Formation (Jarvis & Tocher, 1987).

Macrofossil Biozonation: Jarvis & Woodroof (1984) proposed a largely untested biozonal scheme based on inoceramid bivalves, which is not used herein. Recent work on the successions in south-east Devon shows that the Seaton Chalk Formation of Jarvis & Woodroof (1984) belongs to the Mytiloides spp. Zone (sensu Wood, 1996) & T. lata Zone (Woods, 1999) of standard usage.

Correlation: see Correlation with other lithostratigraphical schemes for south-west England

see Correlation with other UK regions

References

JARVIS, I & TOCHER, B A. 1987. Field Meeting: the Cretaceous of SE Devon, 14 - 16th March, 1986. Proc. Geol. Ass., Vol. 98 (1), 51-66.

JARVIS, I & WOODROOF, P B. 1984. Stratigraphy of the Cenomanian and basal Turonian (Upper Cretaceous) between Branscombe and Seaton, S E Devon, England. Proceedings of the Geologists' Association, Vol. 95 (3), 193-215.

WOOD, C. J. 1996. Upper Cretaceous: the Chalk Group. In SUMBLER, M. G., British Regional Geology: London and the Thames Valley. Fourth Edition. (London: HMSO for the British Geological Survey).

WOODS, M A.1999. Draft contribution to the sheet description of the Sidmouth district (Sheet 326): Cretaceous. British Geological Survey Technical Report, WH/99/28R.

See: Connett's Hole Nodular Chalk Member, Beer Roads Flinty Chalk Member, Ramsgate Chalk Formation, Haven Cliff Neocardioceras Hardground, marl, flint, hardground.