82 PE0F. E. H. L. SCHWAEZ 02s T THE COAST-LEDGES [Feb. 1906, 



3500 to 4000 feet above sea-level, 1 which I have endeavoured to 

 explain by the base-level of erosion being caused by impassable 

 obstructions in the course of the rivers ; and I still do not see my 

 way to offer any other explanation. Had the base-level been the 

 result of the depression of the land, we should obtain a most 

 remarkable physiography for the western part of the Colony : there 

 would have been a narrow fringing reef of mountains, with an 

 immense central lagoon, like an atoll magnified. There are no 

 traces of a 3500 -foot terrace on the coast-sides of the mountains — 

 a fact, however, which might be explained by the great denudation 

 thai takes place on the seaward side of mountain-chains ; even in the 

 dry interior the remains of this plateau are exceedingly scarce, and 

 there would have to be some exceptional cause to allow of such being 

 protected on the coast, did they exist. The only example of which 

 I can think, is the summit of Table Mountain at Cape Town, 

 3549 feet above sea-level ; but I do not wish to press this into the 

 theory, unless many other confirmatory facts can be gathered. 



I have often sat on a mountain-top, and, surveying the enormous 

 landscape that opens out before one in the clear air of South Africa, 

 have noticed how many of the chains of folded mountains cut 

 a level sky-line. I have thought, too, that there might have- 

 been a vast peneplain at elevations of from 5000 to 6000 feet 

 (see fig. 3, p. 81). Such a plain would have left only a few 

 peaks of the folded mountain-region projecting as islands, and it 

 would have included the top of the escarpment of the great inland 

 plateau. This escarpment is now seen as the dolerite-capped hills 

 that face the Great Karroo, the crests of which form the watershed 

 between the streams running into the Orange River and those 

 flowing southwards to the Indian Ocean. 



Turning eastwards, we find the remarkably well-preserved marine 

 plateau near Port Elizabeth and Uitenhage, to which I have already 

 referred in discussing the marine origin of the rock-shelves. The- 

 Uplands plateau comes eastwards to Port Elizabeth, but is, I think, 

 not quite so high above sea-level as at George or Knysna. The 

 plateau, with the shingle and shell-deposits, is only some 150 to 

 200 feet high along the shore, but rises inland to 463 feet at 

 Coerney ; at this level it reaches the next step or escarpment of the 

 higher plateau of about 1000 feet. We know too little about the 

 country beyond this point to discuss the facts further ; but, as 

 I gazed over all this part from a peak on the Baviaan's Kloof, 

 there appeared to be a succession of level plains, cut off by steep, 

 cliffs on the seaward side, beginning with the 4000-foot plateau and 

 sinking gradually to the coastal one of an altitude not exceeding 

 150 to 200 feet. 



At East London there is a remarkable succession of plateaux. 

 The following levels along the railway-line will convey some idea 

 of the nature of the country, if one considers that each of the 



1 ' High-Level Gravels of the Cape, &e.' Trans. S.A. Phil. Soc. vol. xv (1904), 

 pt, 2, p. 43. 



