DISTRICTS OF STRONGER RELIEF 431 



On the way to Victoria falls the country was rougher than any other dis- 

 trict that we traversed on the highland, but all the mountains and hills 

 thereabout seemed to be merely residual eminences of harder rock, like 

 the dolerite ridges and mesas of the Veld. Their survival in no way 

 contradicts the explanation of the Veld by long continued and more 

 effectual erosion. 



The east and west ranges which occupy the southern part of Cape 

 Colony are not mentioned in the preceding paragraph because the broad 

 valleys between them are lower than the highlands of the Veld. These 

 ranges should probably be associated with the mountains and escarpments 

 which roughen the slope where the highlands descend eastward to the 

 Indian ocean, for I gained the impression that in both these areas, south 

 and east of the Veld, the peneplain of the highland had once extended 

 farther toward the sea and had afterward been dissected by short rivers 

 of rapid fall. 



OCCASIONAL DEEP VALLEYS 



A notable feature of all the high standing peneplaned areas that we 

 traversed is their comparative freedom from deeply incised valleys. High 

 standing peneplains are common in many other parts of the world, but 

 they are, with hardly an exception, more or less completely dissected by 

 the rivers that drain them. In South Africa undissected continuity 

 seemed to be the rule and dissection the exception. The rivers flow, one 

 may almost say, on the plain. The only striking example of dissection 

 that we saw within the plateau area was the gorge of the Zambesi below 

 Victoria falls. Here the river has cut down its extraordinary zigzag 

 trench beneath the floor of a very broad and shallow preexistent valley. 

 It may well be, however, that on account of our journey having been so 

 largely by rail, and on account of the railways having been located as far 

 as possible along the broad highland divides between the larger and deeper 

 valleys, as between Bulawayo and Salisbury, that we gained an undue 

 impression of the freedom of the highland from dissection; yet where we 

 crossed the Orange and the Vaal rivers and their branches the valleys were 

 very little, if at all, sunk below the level of the adjoining plains. It 

 should be remembered, however, that the Orange river is described as 

 having falls in its lower course, west of the Veld, and it is to be presumed 

 that these falls are associated with a more or less distinctly entrenched 

 valley. Special physiographic observation is much needed on this point. 



VICTORIA FALLS OF THE ZAMBESI 



The peculiar zigzag pattern of the "Batoka gorge" of the Zambesi river 

 below Victoria falls has been well shown by Molyneux to depend on the ex- 



