Publications
The junction of the Gault and Lower Greensand in East Sussex and at Folkestone, Kent: Weald Research Committee Report No. 42, by R. Casey, F.G.S., published 1950 in The Proceedings of the Geologists' Association London (no. 61 issue 4, article, pp.268-298) View Online
Abstract:Gault and Lower Greensand are parts of an essentially continuous and conformable series; their line of demarcation is often arbitrary and has no fixed time-relationship. In the Lewes-Eastbourne district of Sussex, for example, the basement-beds of the Gault are the age-equivalents of almost the whole of the Folkestone Beds of the Lower Greensand as developed at Folkestone, the nodosocostatum, tardefurcata, and mammillatum zones of the Albian all being represented in 3-4 feet of glauconitic sandy clay with phosphatic nodules. The presence of the nodosocostatum zone is here indicated by the jacobi fauna, the first authentic record of its occurrence in England since its discovery at Folkestone in 1939. Conversely, the sands which underlie the Gault in this part of Sussex are regarded as an expanded version of the bottom few inches of the Folkestone Beds at Folkestone and are compared with the sands below the nodule-bed with H. jacobi at Wissant, in the Bas Boulonnais.
The diachronous base of the Gault in East Sussex, previously thought to indicate transgressive overlap, may now be ascribed to the progressive assumption by the top beds of the Lower Greensand of the Gault facies as they extend towards the coast, thereby partly accounting for the rapid south-easterly thinning of the Lower Greensand in East Sussex. This hypothesis is advanced as the explanation for the apparent disappearance of the Folkestone Beds under Eastbourne.
Condensed and incomplete faunal successions are demonstrated in both areas and the significance of phosphatic nodule-beds in unravelling the relations of Gault and Lower Greensand is discussed. Some modifications of current views on the faunal sequence in the Folkestone Beds and basal Gault at Folkestone are introduced. The Lower Albian ammonite Hypacanthoplites is illustrated for the first time from a British occurrence.
The diachronous base of the Gault in East Sussex, previously thought to indicate transgressive overlap, may now be ascribed to the progressive assumption by the top beds of the Lower Greensand of the Gault facies as they extend towards the coast, thereby partly accounting for the rapid south-easterly thinning of the Lower Greensand in East Sussex. This hypothesis is advanced as the explanation for the apparent disappearance of the Folkestone Beds under Eastbourne.
Condensed and incomplete faunal successions are demonstrated in both areas and the significance of phosphatic nodule-beds in unravelling the relations of Gault and Lower Greensand is discussed. Some modifications of current views on the faunal sequence in the Folkestone Beds and basal Gault at Folkestone are introduced. The Lower Albian ammonite Hypacanthoplites is illustrated for the first time from a British occurrence.