The following paper deals with that part of the South Downs which adjoins the coast between Beachy Head and Newhaven. Its primary object was to investigate the variations of the dip and strike of the Chalk strata in that area, with the view of discovering the interpretation of the sudden westerly dip of the Chalk at Seaford Head. Incidentally, the geological features of the surrounding country and their relation to the surface-contours are discussed, and reasons are given for the view that the true eastern extremity of the structural area known as the Hampshire Basin lies within this district. With regard to previous literature on this part of Sussex, the whole question is summed up by Mr. Jukes-Browne in the following statement, published in 1904:— ‘At Newhaven the beds are nearly horizontal, so there must be a quick recovery from the steep inclination which they show in Seafurd Head. Whether they are re-curved or faulted we have no means of knowing.’