The North and South Downs, with all the country between them, form part of a great fold or outward bulge of the strata above enumerated, having its centre about the middle line of the Forest Ridge. Imagine these strata bent or pushed upward by an internal upheaving force acting along that line, and you will get a rough picture of the original circumstances which have led to the existing arrangement of the county. You would then have, instead of a flat table-land, as supposed above, a great curved mountain slope, with its centre on top of the Forest Ridge. This gentle slope would rise from the sea between Chichester and a point south of Beachy, would swell slowly upward till it reached a height of two or three thousand feet at the Surrey border, and would fall again gradually towards the Thames valley at London. On the southern side of the Downs this is pretty much what we now get, the Tertiary strata being preserved in the district near Chichester; though farther east, around Newhaven and Beachy Head, the sea has encroached upon the chalk so as to cut out the great white cliffs which bound the view everywhere along the shore from Brighton to Eastbourne. In the central portion of the boss, however, almost all the highest elevated part has been denuded by ice or water action. Between the North and South Downs, where we ought to find the mountain ridge, we find instead the valley of the Weald. Here the chalk has been quite worn away, giving rise to the steep escarpment on the northern side of the South Downs, seen from the Devil's Dyke, so that at the foot of the sudden descent we get the Weald clay exposed; while in the very centre of the upheaved tract the clay itself has been cut through, and the Hastings sand appears upon the surface. Moreover, the sand, being upraised by the central force, stands higher than the clay on either side, which forms the trough of the Weald; and thus the forest ridge, which abuts upon the sea in the cliffs of Hastings Castle, seems to lie above the clay, under which, however, it really glides on either side. I need hardly add that this rough diagrammatic description is only meant as a general indication of the facts, and that it considerably simplifies the real geological changes probably involved in the sculpture of Sussex. Nevertheless, I believe it pretty accurately represents the main formative points in the ante-human history of the county.