346 DRAINAGE OF THE GREAT VALLEY. Chap. XXVI. 



lakes hitherto discovered are shallow, in consequence of being 

 the mere residua of very much larger bodies of water. There 

 can be no doubt that this continent was, in former times, 

 very much more copiously supplied with water than at 

 present, but a natural process of drainage has been going on 

 for ages. 



In addition to the indications already noticed, the river- 

 courses themselves bear testimony to the original lacustrine 

 condition of this region, for they bear a strong resemblance to 

 the depressions left in the mud of a shallow pool of water 

 which has been drained off by an artificial duct. None of the 

 rivers in the valley of the Zambesi have slopes down to their 

 beds. Indeed, many are much like the Thames at the Isle of 

 Dogs, only that the Zambesi has to rise twenty or thirty feet 

 before it overflows its meadows. The rivers have each two 

 beds, — one of low water, a simple furrow cut sharply out of the 

 calcareous tufa which lined the channel of the ancient lake ; 

 and another of inundation. When the beds of inundation are 

 filled, they assume the appearance of chains of lakes. Many 

 of the rivers are very tortuous in their course, the Chobe and 

 Simah particularly so ; and if we may receive the testimony 

 of the natives, they form a complicated network. For in- 

 stance, they assured me that communications exist between 

 the upper courses of the Simah and the Chobe, and between 

 the Simah and the Kama to the south of the Zambesi, and 

 between the Kafue and the Loangwa to the north of that 

 river. And even though the interlacing may not be quite to 

 the extent believed by the natives, the country is so level 

 and the rivers so tortuous that I see no improbability in the 

 conclusion that there is a network of waters of a very peculiar 

 nature in this region. The reason why I am disposed to 

 place a certain amount of confidence in the native reports 

 is this, that in 1851 Mr. Oswell and I, being unable to ascend 

 the Zambesi, employed the natives to draw a map embodying 

 their ideas of that river. My own subsequent explorations 

 of the river proved the general correctness of this map, and 

 therefore I think that their views of the courses of other rivers 

 are not unworthy of attention. 



24£h. — At the village of Moyara we left the valley in which 

 the Lekone flows, as it here trends away to the eastward. 



