The Essex Naturalist
5
THE 1998 PRESIDENTIAL ADDRESS
The geological history of the Lower Thames in Essex - A review
Peter Allen
Abstract
This review considers the processes and stratigraphic procedures hy which the
terraces of the Lower Thames are recognised and interpreted and briefly
describes the history of the river and the distribution of its terraces. An
indication is given of the present state of knowledge, the problems yet to be
resolved and the international significance of the area geologically.
Fig. 1. Location map and geology of the Lower Thames (after Bridgland, 1994).
Introduction
The Middle and Lower Thames occupy a synclinal basin formed of Cretaceous
rocks (Fig. 1) and partly infilled with Tertiary sands, gravels and clays, mostly of
marine origin, the last pre-Thames deposits being Crag sands. The Crag sea
formerly extended across the London Basin as far west as Netley Heath neat