The Lower Thames Valley is a classic area for British Pleistocene studies. The valley contains a sequence of River Thames deposits representing approximately the last 300,000 years, including older, highly fragmented and eroded sediments derived from Thames tributaries and glaciation. The region includes some of the most important palaeolithic archaeological sites in the country which, although extensively studied, have never previously been fitted into a regional context. The area also includes some of the most important fossiliferous localities in the country, several of which have been at the centre of controversies regarding the sequence of events in the British Pleistocene. This regional investigation clarifies the problems by presenting the geological sequence in detail and establishing the relationship of these localities for the first time.