l88 THE DESICCATION OF AFRICA, 



in procuress, as is evidenced by the frefjuent earthquakes 

 emanating from that quarter. 



To join up these valleys, which are separated by a distance 

 of over 800 miles, and reconstruct in the imagination the channel 

 of a hypothetical Proto-Orange is thus, to say the least of it. not 

 justifiable. 



Taking the present physiography of South-Central Africa 

 as a basis, it appears more probable to me that the waters of the 

 Okavango and Kwando, and also possibly of the Upper Zambesi, 

 at one time flowed into the Indian Ocean z'ia the Makarikari 

 depression and the Limpopo Valley, and that they were diverted 

 to the courses they now take either by a regional uplift or north- 

 ward tilting of the Central Kalahari, or, as suggested by Pro- 

 fessor Schwarz, by the headstream erosion of what is now the 

 Lower Zambesi. In the absence of an accurate topographical 

 map oif the Makarikari Basin and the area to the east of it, I 

 hesitate, however, definitely to put forward the theory. 



Turning to Professor Schwarz's project for the re-flooding 

 of Lake Ngami, I agree with the author that the waters of the 

 Kunene could be turned into the Etosha Pan by building a weir 

 across the river above Kinga. His statement that the flood 

 waters of the Kunene. after filling the Eto'sha Pan, " work their 

 way up the Omuramba Ovambo, and eventually by the Omatako 

 reach the Okavango River," however, is not only incorrect but 

 misleading, inasmuch as the Omuramba Ovambo is a very clearly 

 defined watercourse with a pronounced fall towards the west, 

 which is separated from the Omuramba Omatako by a tract of 

 elevated sand-veld. 



The Onuiramba Omatako became a raging torrent during the 

 rainy season, 1908-1909 — the statement, by the way, is taken 

 from my memoir on " The Geology and Mineral Industry of 

 South-West Africa " — not because of the flooding oif the Etosha 

 Pan by the Kunene, but because of the abnormal rains that fell 

 in the Grootfontein and Waterberg districts in that season. 



Speaking from personal knowledge O'f the area, I can assure 

 Professor Schwarz that the flooding of the Etosha Pan, to a 

 depth sufficient to make the Kunene flow 7'ia the Omuramba 

 Omatako into the Okavango, would require far more water than 

 the Kunene is capable of supplying, quite apart from the fact that 

 ic would result in the submergence of the whole of Ovamboland 

 and considerable portions of the fertile Grootfontein and Out jo 

 districts. This part of the project is therefore, in my opinion, 

 not worthy of serious consideration. 



In regard to the diversion of the waters of the Okavango 

 and Kwando Rivers intO' the N'Gami depression by erecting a 

 barrage across the Chobe, about 30 miles from its confluence with 

 the Zambesi, it appears to me, having regard to the fact that 

 these rivers, on entering the N'Gami region, flow in broad 

 marshy valleys with low banks bordered by very flat country, 

 that, instead of creating a greater Lake N'Gami, the efifect of 

 raising the level of the Chobe. in the manner suggested, would 



