1 66 THE DESICCATION OF AFRICA. 



be created, a sheet of water about double the size of Tangan- 

 yika and more than half the size of Victoria Nyanza. 



The Soa and the Ngami Lake are connected by the 

 Botletle River and the relationship between the two is the 

 same as that between the Bodele and Lake Chad, the Botletle 

 River representing the Bahr-el-Ghazal. To the south-west of 

 the Soa Pan there is another pan, Andersson's Vley, con- 

 nected by a dry river-bed, or "omuramba," with the Soa 

 system, and from here to the Molopo River there are the sand 

 hills of the Kalahari; these are what the French call " Ergs 

 morts," that is, dunes that have been anchored by vegetation. 

 The sand belt occupies the centre of the course of the original 

 great river of South Africa, which T am going to call the Proto- 

 Orange, in accordance with the nomenclature adopted in the 

 case of the North African rivers. This river failed owing to 

 the capture of its head waters- 



The original central South African river, this Proto- 

 Orange, rose in the highlands about Tanganyika and is now 

 called the Loangwe River. This flows south-west and joins 

 the Zambesi near Zomba; thence it originally flowed up the 

 channel of the Zambesi to Wankie, where it met the Batoka 

 basalts, and then followed a course parallel to the Deka fault, 

 in a valley, the Gwai Poort, still open to it, to the Soa Pan. 

 From the Soa Pan it flowed to Andersson's Vley and the 

 Molopo River at Mokopon, and so out to sea by the lower 

 Molopo and the Orange River. Livingstone, in his " Mission- 

 ary Travels," 1857, p. 477, alludes to the ancient river which 

 once flowed from the Linyanti (Chobe) basin to the Orange 

 River, so I am stating no new idea of my own, but rather 

 developing the facts recognised by actual travellers. 



The original coastal rampart, on the east, was the Kirk 

 range, that skirts the western shore of Lake Nyasa and is 

 continued on the south, as the Melsetter Range; this latter 

 forms the boundary between Southern Rhodesia and Mozam- 

 bique. The original Zambesi rose in these hills and flowed 

 south-east to the sea. On the inland side the river ran 

 in its present channel, but north-westwards and then west- 

 wards, to join the Loangwe River. The original rampart is 

 now much degraded by weathering and erosion where the 

 Zambesi traverses it; at one time it was, judging from some 

 of the peaks left standing, like Mt. Dombo, 6,240 feet, at a 

 general average height of 6,000 feet, which is a constant 

 level for all the coastal ranges of South Africa- From this 

 range the Zambesi had a run of 350 miles to the sea, or a 

 fall of 17 feet to the mile. On the inland side the river had 

 a course of between 2,500 and 3,000 miles, or about two 

 feet to the mile; in other words, the erosive power of the coast 



