The London Clay comprises a sequence of silty clay, clayey silt and sandy clayey silt, with partings and find sand at some levels, and thin beds of sandy silt and silty sand.

Chris King has divided the Sheppey sequence into fourteen lithostratigraphic units designated SH-1 to SH-14 in ascending order. Boundaries between these units are generally transitional, and due to the monotonous lithology it is necessary to examine the sections closely in order to identify and distinguish successive units.

This succession (copied from David Ward's Field Guide) is a composite sequence drawn up from measurements by King made at a number of different sites between Warden Spring and Round Hill.The septarian nodule layers have been used as datum levels for the measurements and are lettered from A to P in ascending order.

The datum is the base of unit SH-1. Isolated nodules occur sporadically at other levels. Due to the generally northerly to north-westerly dip, the lowest beds are exposed at the south-eastern end of the coastal section in Warden Bay.

Progressively higher beds outcrop at beach level from here to Paddy's Point. The London Clay sequence exposed at Sheppey is 53 meters thick, overlain by a maximum thickness of 10meters of the Virginia Water Formation. The Abbey Gatehouse sits on the top of the Virginia Water Formation