Chap. XXIV. PHENOMENON OF THE LOTEMBWA. 315 



we pursued our way, and on the 8th of June we forded the 

 Lotembwa to the N.W. of Dilolo, and regained our former 

 path. The Lotembwa here is about a mile wide, about three 

 feet deep, and full of the lotus, papyrus, arum, mat-rushes, 

 and other aquatic plants. I did not observe the course in 

 which the water flowed, while crossing ; but I supposed it to 

 be simply a prolongation of t-he river which we had seen on 

 our previous progress running southwards from lake Dilolo. 

 When, however, we came to the Southern Lotembwa, we 

 were informed by Shakatwala that the river we had crossed 

 flowed in an opposite direction, — not into Dilolo, but north- (61) 

 wards into the Kasai. This phenomenon of a river running 

 in opposite directions struck even his mind as strange ; but I 

 hav? no doubt that his assertion was correct, and that the 

 DiloiO is actually the watershed between the river systems 

 that flow to the east and west. I now for the first time ap- 

 prehended the true form of the river systems and continent. 

 I had learnt, partly from my own observation and partly from 

 Information derived from others, that the rivers of this part of 

 Africa took their rise in the same elevated region, and that all 

 united in two main drains, the one flowing to the N. by the 

 Congo, and the other to the S. by the Zambesi. I was now 

 standing on the central ridge that divided these two systems, 

 and I was surprised to find how slight its elevation was : 

 instead of the lofty snow-clad mountains which we might 

 have expected, we found perfectly flat plains not more than 

 4000 feet above the level of the sea, and 1000 feet lower than 

 the western ridge we had already passed. I was not then 

 aware that any one else had discovered the elevated trough 

 form of the centre of Africa. I had observed that the old 

 schistose rocks on the sides dipped in towards the centre of 

 the country, and that their strike nearly corresponded with 

 the major axis of the continent ; and also that, where the later 

 erupted trap-rocks had been spread out in tabular masses over 

 the central plateau, they had borne angular fragments of the 

 older rocks in their substance. This latter feature was always 

 a puzzle to me, till favoured with Sir Roderick Murchison's 

 explanation* of the original form of the continent, for then 



* After dwelling upon the geological structure of the Cape Colony as developed 

 by Mr. A. Bain, and the existence in very remote periods of lacustrine condition! 



