THE DESICCATION OF AFRICA. 177 



The Molopo River enters the Orange River below the great 

 bar of granite at the Aughrabies Falls. The whole of the area 

 under discussion, that is to say, the drainage area of the 

 Proto-Orange, is a plateau inclined to the south-west, and we 

 have assigned to it its natural outlet. This Proto-Orangc has 

 been beheaded ; its head streams have been diverted by the 

 Zambesi, and the central portion has been bereft of its 

 natural aliment and has become a desert. Luckih', its southern 

 affluents, the present Orange and Vaal Rivers, still have water 

 in them, but the same process is going on all round the basins 

 of their head streams, the coastal streams are eating back 

 through the girdle of the coastal rampart, and every year more 

 and more water is being hurried precipitously to the sea, 

 instead ©f going the long journey across the continent, where 

 it can do some good. 



In Cape Colony, the rampart of dolerite-capped hills of 

 the Karroo guard the inland waters, what little is left of them, 

 the tough nature of the rock yielding very gradually to the 

 agencies of Weathering and erosion, but still the Great Fish 

 River has eaten a great bite out of the inner drainage area. 

 The dolerite-capped escarpment of the Karroo is a secondary 

 water-shed and stands in the same relationship to the coast 

 ranges, as the Batoka basalts of the Victoria Falls stand tb 

 Kirk and Melsetter Ranges. In the Transvaal, we see the 

 Komati River stealing into the territory of the Vaal River; the 

 Olifants River draining inland as far as Pretoria, and the 

 Limpopo River reaching back even to the outskirts of the 

 Kalahari. Further north, the Sabi River has pierced the 

 Melsetter barrier range and drains the whole country from 

 Bulawayo to Salisbury ; finally the Zambesi sends back its 

 tentacles almost to the West Coast. Every one of these rivers 

 started originally at the coastal rampart and has eaten back 

 by headstream erosion. The waters inside the barrier-ranges 

 once flowed towards Central South Africa and made the 

 central depression a land of running rivers and of great 

 fertility. 



We cannot hope to bring all or any of these rivers back 

 to their original courses, and to w^eir up the inland streams is 

 simply to check their flow and to give a further advantage to 

 the vigorous coastal streams. We can, however, stop the 

 further desiccation of the central portions of South Africa by 

 building two weirs, one across the Cunene River, below Kinga, 

 and the other across the Selinda River, or, better still, across 

 the Chobe River, between the swamps and the Zambesi. The 

 study of any good map of South Africa will show one how 

 the steep, coastal rivers are stealing inland and draining the 

 waters that flow towards the centre, so that the waters that 

 once went to fertilise the plains are turned back and hurried 



