We have seen that the unison of the Downs is broken by a certain number of regular gaps--the valleys, that is, of the Wealden rivers. For the rivers of Sussex, by an accident which geologists have attempted to explain, are not determined by the rise of these great hills, but on the contrary cut right through them from the Weald to the sea. The Arun, from the Wealden town of Pulborough to its seaport of Littlehampton, the little Adur from various sources round by Shipley and Cuckfield to its harbour town of Shoreham, the Ouse from the Wealden town of Uckfield to its harbour town of Newhaven, all cut right through the chalk hills and form narrow, level valleys of alluvial soil between one section of the Downs and the next. These valleys where they cut through the Downs were never used for roads before modern times. The good road along the little Adur to Shoreham is fairly old, but it must be remembered that at this point the Downs come very close to the sea. Along the Ouse and along the Arun no road was attempted until quite lately. There does now exist, and perhaps has existed for two or three hundred years past, a road from Lewes to the mouth of the Ouse, but even to-day there is none along the Arun valley. The soil was too marshy for such a road to be constructed in early times, and the dry hill-way once fixed and metalled has become the only permanent road to Arundel. The afforesting of the range of the Downs is worthy of remark. The woods are of two kinds--those that crown the foot-hills towards the sea and here and there the high slopes of the Downs themselves, and those that have caught on to the slight alluvial drift of the hollows. In both cases they are principally of beech, while in the open around them, along the old tracks and clinging to the crest of the escarpments, are lines of very ancient and somewhat stunted yews. In both cases, whether over the round of the hills or in their hollows, the Sussex woods are somewhat limited in extent and fairly clear of undergrowth. Through all the forest [Illustration: FITTLEWORTH BRIDGE] [Sidenote: THE BEECH AND THE YEW] known as the Nore Wood a man can ride his horse in pretty well any direction without following a path; the same is true of Houghton Forest and of the other large woods of the Downs. This ease they owe to two things: first, the character of the beech-trees, which forms under its branches a thick bed of mast, out of which but few spears of greenery will show; and, secondly, that quality of the chalk by which (to the salvation of Sussex!) it is but slightly fertile, and by which it therefore preserves itself intact from the invasion of man. Indeed, it is remarkable that the two trees of the Downs, the yew and the beech, both make for a clear soil, and there is a proverb in those parts-- Under the Beech and th’ Yow Nowt’ll grow.