Supplementary Note on the Walton-Common Section

Abstract

There seems to be so much uncertainty as to the character of the basal beds of the Lower Bagshots in the London Basin that any opportunity which affords us unmistakable evidence of their real nature should be seized without delay. We have had so much theorizing, based upon the evidence of well-sections and of limited exposures, that we turn with pleasure to a good continuous section like the one which has lately been disclosed between Walton and Weybridge on the London and South-Western Railway. The main features of the Lower Bagshot series in this section, at its actual junction with the London Clay, were very fully described by me in a communication made to the Society last year. Whether we regard the junction there shown as evidence of an unconformity or otherwise, the fact of a complete lithological change is patent to all. 1. Recapitulation of some points in the previous paper. Resting immediately upon the grey-coloured and sticky London Clay, distinguished by its fine and perfectly regular bedding, is a sharp yellow sand full of current-bedding. This yellow sand I dabbed “No. 1 Bagshots.” Then follows the first clay series, which I called No. 2, or the “Blue Bagshots.” It is surmounted by a second sandy series, referred to in my previous paper as “No. 3 Bagshots.” As far as the new cutting for the widening of the line had then progressed, there was no reason to suppose that No. 3 was succeeded by a second clay series, beyond