FORMER EXTENSION OF SOUTH AFRICA 443 



after the time of deformation of these systems, South Africa had a 

 greater extension on the east, south, and west than it has now. 



Fully as important as any of the preceding considerations are the 

 inferences as to a former greater extension of South Africa, based on the 

 distribution of fossil and recent plants and animals, as discussed by 

 various geologists and biologists; but this aspect of the problem will not 

 be further stated here. 



In view of all these suggestive inferences, it is at least highly probable 

 that the Veld was formerly bordered on the east, south, and west, as it is 

 still on the north, by a large extent of land. Thus surrounded, the cli- 

 mate of the region would have been drier than it is now. It then seems 

 possible that the combination of these two conditions, greater area and 

 drier climate, both of which are essential to the accomplishment of arid 

 leveling independent of normal baselevei, along with the third essential 

 of a long undisturbed quiescence, may have sufficed to produce the high- 

 land peneplain in about its present altitude by the processes of arid 

 erosion, and that the dissection which is now beginning may be the result, 

 not of the elevation of the Veld itself, but of a down-warping of its bord- 

 ers, with the accompanying change to moister climate, whereby many 

 formerly interior drainage systems might have been given free and steep 

 discharge to the sea. 



It next remains to be seen whether the date at which such down- 

 warping could have taken place is consistent with the relatively moderate 

 amount of dissection that the Veld has since then suffered. 



DATE OF ORIGIN OF THE PRESENT COASTLINE 



The occurrence of Cretaceous strata with marine fossils along the 

 southern and eastern coasts shows that those parts of the continent at 

 least lay close to or a little below sealevel in Cretaceous time. Hence, if 

 the interior highland was eroded at its present height as a part of a larger 

 continental area, the rest of which has been bent down so as to bring the 

 sea closer to the area of the existing highland than it was originally, the 

 diminution of size must have taken place at least as long ago as early 

 Cretaceous time. As a result, the eastern border of the highland must 

 have been exposed to active retrogressive erosion all through the Tertiary 

 time. If, on the other hand, the highland owes its present altitude to 

 uplift after normal peneplanation, the date of uplift may be associated 

 with the movement by which the marine Cretaceous formations were ex- 

 posed along the eastern and southern coasts; and this movement may 

 have taken place in any part of post- Cretaceous time except the most 

 recent. The question now to be determined, is whether the more ancient 



