Southern Region Chalk Group Lithostratigraphy: Sussex lithostratigraphy of Mortimore (1986a) - Belle Tout Beds
The Belle Tout Beds, c. 17 m thick in Sussex, are marked by the upper of the two Shoreham Marls at the base, and the Seven Sisters Flint at the top (Mortimore, 1986a). They comprise soft, flinty chalk with at least three marl seams (Belle Tout Marls), and locally a bed of spongiferous, nodular chalk (Warren Sponge Bed) (Mortimore, 1986a). The flints in this interval, in common with much of the remainder of the Seaford Chalk, show a tendency to laterally coalesce, forming semi-tabular and tabular flints.
The fauna is characterised by laterally persistent shell drifts of the inoceramid bivalve Platyceramus (Mortimore, 1986a). These are characteristically large, flattened shell fragments, and some shells may approach a metre across. Towards the Seven Sisters Flint, Platyceramus becomes thicker shelled (+5 mm), and is associated with acmes of the distinctively inflated inoceramid bivalve Volviceramus involutus. Rare Volviceramus koeneni occur near the base of the Belle Tout Beds (Mortimore, 1986a), associated with undescribed Cremnoceramus. The characteristic echinoid is Micraster turonensis (Mortimore, 1986a).
Macrofossil Biozonation: lower M. coranguinum Zone
Correlation: see Correlation with other Southern Region Chalk Group classifications
see Correlation with other UK Chalk Group successions
MORTIMORE, R N.1986a. Stratigraphy of the Upper Cretaceous White Chalk of Sussex. Proceedings of the Geologists' Association, Vol. 97(2), 97-139.
See: flint, marl, Seven Sisters Flint