The Folkestone Warren landslides are first compared to the landslides at geologically related sites on the northern coast of France and the southern coast of England. Additional historical data is then presented on the Warren landslides, particularly that of 1915, and the influence on these of the interruption of littoral drift produced by the Folkestone Harbour works is examined. An indication is also given of other considerable mass shiftings which have taken place in the Warren since the early nineteenth century. A preliminary morphological study is made, the features being linked, where possible, with the historical data. The degree to which the frequent Chalk falls from the High Cliff are controlled by the joint pattern is briefly examined and the recent subsurface investigations in the Horse's Head area are reviewed and discussed.
The existing back-analyses of the slips are critically re-examined in the light of the fresh historical and morphological data and additional back-analyses are carried out. Measurements of the residual strengths of the high and low liquid limit Gault are made, in two different ring shear machines, and compared with the combined results of the back-analyses.