South Downs - Geography

Geography

The South Downs is a long chalk escarpment that stretches for over 70 miles (110 km), rising from the valley of the River Itchen near Winchester, Hampshire, in the west to Beachy Head near Eastbourne, East Sussex, in the east. Behind the steep north-facing scarp slope, the gently inclined dip slope of undulating chalk downland extends for a distance of up to 7 miles (11 km) southwards. Viewed from high points further north in the High Weald and on the North Downs, the scarp of the South Downs presents itself as a steep wall that bounds the horizon, with its grassland heights punctuated with clumps of trees (such as Chanctonbury Ring).

In the west, the chalk ridge of the South Downs merges with the North Downs to form the Hampshire Downs. In the east, the escarpment terminates at the English Channel coast between Seaford and Eastbourne, where it produces the spectacular white cliffs of Seaford Head, the Seven Sisters, whose undulations reveal a cross-section through a pre-existing landscape of parallel ridges and dry valleys that has been exposed as the high chalk headland has receded through erosion by the sea, and Beachy Head, the highest chalk sea cliff in Britain at 162 metres (531 ft) above sea level.

The South Downs may be said to have three main component parts: the East Hampshire Downs, the Western Downs and the Eastern Downs, together with the river valleys that cut across them and the land immediately below them, the scarpfoot. The Western and Eastern Downs are often collectively referred to as the Sussex Downs. The Western Downs, lying west of the River Arun, are much more wooded, particularly on the scarp face, than the Eastern Downs. It is the bare Eastern Downs - the only part of the chalk escarpment to which, until the late 19th century, the term "South Downs" was usually applied - that has come to epitomise, in literature and art, the South Downs as a whole and which has been the subject matter of such celebrated writers and artists as Rudyard Kipling (the "blunt, bow-headed, whale-backed downs") and Eric Ravilious.

Four river valleys cut through the South Downs, namely those of the rivers Arun, Adur, Ouse and Cuckmere, providing a contrasting landscape. Chalk aquifers and to a lesser extent winterbourne streams supply much of the water required by the surrounding settlements. Dew ponds, artificial ponds for watering livestock, are a characteristic feature on the downland.

The highest point on the South Downs is Butser Hill, whose summit is 270 metres (890 ft) above sea level. The plateau-like top of this vast, irregularly shaped hill, which lies just south of Petersfield, Hampshire, was in regular use through prehistory. It has been designated as a National Nature Reserve.

Within the boundary of the South Downs National Park, which includes parts of the western Weald to the north of the South Downs, the highest point is Blackdown, West Sussex, which rises to 280 metres (919 ft) above sea level. However, Blackdown geologically is not part of the South Downs but instead forms part of the Greensand Ridge on the Weald's western margins.

A list of those points on the South Downs above 700 feet (210 m), going from west to east, is given below.