90 SOUTH AND EAST AFRICA. Throughout its lower course the Orange receives no perennial contributions from any direction, the gorges which open in the quartz cliffs to the right and left of its valley being for the most part merely the winding sand-beds of intermittent or altogether dried up affluents. Hence as it approaches the sea it decreases in volume, and although the main stream is over 40 feet deep during the great floods, it may be forded for most of the year at certain points where a transverse passage is presented by the lateral ravines facing each other on both banks. But in the deep rocky gorge by which it pierces the coast range on its seaward course, the Orange is almost inaccessible from either side. At several points the overhanging escarpments of the surrounding plateaux rise several hundred yards above its channel, and the traveller might perish of thirst without finding a single fissure or practicable track leading down to the tantalising stream which he sees flowing at his feet. The river, barred at every turning by projecting rocky ledges, rushes in abrupt meanderings between the enclosing granite cliffs, and at one point even trends sharply to the south, flowing for some distance in this direction before it finds an opening in the last barrier obstructing its course to the sea. Above the bar its waters are collected in an extensive lacustrine basin, above which hover countless flocks of aquatic birds. It frequently happens that this basin becomes completeh cut off from the sea by an intervening strip of sand. During the fluvial inunda- tions the swift current opens a broad channel to the Atlantic ; but even then it is inaccessible to shipping owing to the submarine banks resting on elevated rocky plateaux, where the surf beats incessantly. Hence vessels bound for this part of the coast are obliged to land at the small inlet of Cape Voltas, lying to the south of the Orange estuary. Thus this great river, which has a total course of no less than 1,300 miles, draining an area of over 500,000 square miles, is as useless for navigation as it mostly is for irrigation purposes. The Olifaxt, Breede, Great Fish, and Kei Rivers. None of the rivers reaching the Atlantic between the Orange and the Cape of Good Hope, or for some distance east of that point, have room to develop a long course in the narrow space separating the coast ranges from the sea. Nor do any of them send down a great volume of water, notwithstanding the relatively heavy rain- fall in this region. On the west side the largest is the Olifant, that is "Elephant," Biver, which flows mainly in a north-westerly direction to the sea above St. Helena Bay. On the southern slope the Breede-rivier ("Broad River") collects the surface Avaters from the uplands round about Capetown, and reaches the coast east of Cape Agulhas through a channel accessible to vessels of 150 tons. Notwithstanding its comparatively small size the Breede is the only stream in Cape Colony which has a seaport on its banks. Some miles farther east the Southern Ocean is reached by the Groote-rivier (" Great River "), called also the Gaurits, whose ramifying fluvial system resembles the widespread branches of an oak. The Gamtoa, or Gamtoos, which like the Gaurits rises on the plain of the Great Karoo, and like it also forces the parallel coast ranges through a series of romantic
