On the Lower Part of the Upper Cretaceous Series in West Suffolk and Norfolk

Abstract

The zonal subdivisions of the Cambridgeshire Chalk were first described in 1880, and more fully in the Memoirs of the Geological Survey, in 1881, the outcrops of the Totternhoe Stone and the Melbourn Rock having then been traced as far as Burwell and Newmarket respectively; but the survey of the Suffolk Chalk having been previously completed, the lines were not continued on the Survey map. The section exposed in the cliffs near Hunstanton has often been described, but the beds there seen are very different from those which occupy a similar stratigraphical position near Newmarket; it was evident, therefore, that between these two places the beds forming the lower part of the Chalk underwent a considerable amount of lateral change, and that, until more was known of the manner in which one facies of the Lower Chalk passed into the other, no correlation of the Norfolk and Cambridge sections could be more than suggestive. Moreover, in the absence of this information, one of us has found much difficulty in correlating the subdivisions of the Lincolnshire Chalk with that of the Midland counties, and he felt that when once the constitution of the Norfolk Chalk was properly understood, that of Lincolnshire, which bears great resemblance to it, would no longer offer any difficulty. It being clear, therefore, that important issues depended upon an investigation of the changes that take place in the Cretaceous rocks as they pass from Suffolk into Norfolk, it was with the object of exploring this terra incognita