Southern Region Chalk Group Lithostratigraphy: Sussex lithostratigraphy of Mortimore (1986a) - Ringmer Beds

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The Ringmer Beds, 6-8 m thick in the Lewes district (Lake et al., 1987), are marked by the Caburn Marl at the base and the base of Bridgewick Marl 1 at the top (Mortimore, 1986a). They comprise strongly nodular flinty chalk at the base and top, and slightly softer chalk in between (Mortimore, 1986a). The top of the Ringmer Beds contains conspicuously large, black flints, named the Bridgewick Flints (Mortimore, 1986a). These flints form the lower part of the 'Basal Complex' at Dover, and thus mark the junction of the traditional Middle Chalk and the Upper Chalk as defined in the Southern Region (Mortimore & Wood, 1986).

The fauna of the Ringmer Beds is dominated by echinoids, especially Sternotaxis plana, Micraster corbovis and Epiaster michelini (Lake et al., 1987). Brachiopods include Orbirhynchia dispansa, and large inoceramids, probably related to Inoceramus cuvieri, are also distinctive (Lake et al., 1987). The lower part of the Ringmer Beds contains a local acme of the small, wheel-like bryozoan Bicavea rotaformis, which has proved useful for establishing correlations with successions elsewhere (Mortimore & Wood, 1986).

Macrofossil Biozonation: top T. lata Zone & basal S. plana Zone

Correlation: see Correlation with other Southern Region Chalk Group classifications

see Correlation with other UK Chalk Group successions

References[edit]

LAKE, R D, YOUNG, B, WOOD, C J & MORTIMORE, R N. 1987. Geology of the country around Lewes. Memoir of the British Geological Survey.

MORTIMORE, R N.1986a. Stratigraphy of the Upper Cretaceous White Chalk of Sussex. Proceedings of the Geologists' Association, Vol. 97(2), 97-139.

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.

See: marl, flint, nodular chalk,Basal Complex, Upper Chalk (Traditional classification for Southern Region),