This report summarises work undertaken in support of the Ground Movements: Shrink/Swell Project undertaken as part of the BGS Physical hazards Programme. It provides petrographical descriptions acquired using scanning electron microscopy (SEM) of a suite of samples (n =24, from 9 sites) from the Wealden Group (Wessex Clay, Weald Clay and Wadhurst Formations) Clay from the Weald and Wessex Basins of southern England