High-level Gravels of the Cape. 53 



— that is, belong to a later bevel of erosion. It is an extraordinary 

 thing, that throughout the Witteberg hills which lie to the north of 

 the Zwartebergen and are continued towards Grahamstown, the tops 

 are all ground flat to a level from 3,500 to 4,000 feet above the sea, 

 and this in spite of the fact that the strata of which they are com- 

 posed are contorted into the most abrupt and intricate folds. On 

 the inside of the Cederbergen we get the same Witteberg hills, but 

 the strata there are lying almost flat, and the phenomenon of their 

 being flat-topped did not therefore excite any particular attention 

 when they were surveyed, but in spite of the horizontality of the 

 component beds I now believe the actual summits of the hills are 

 due to a base-levelling similar to that which has reduced the folded 

 region to the east of them. Points on these hills do certainly rise 

 so high that one cannot include them with the peneplain ; for 

 instance, the hill to the north of Willowmore called Aasvogel Berg, 

 is 4,400 feet, but this, I take it, is either a portion that has escaped 

 the levelling, forming, as it were, an island, or has since been raised 

 by earth movements, either explanation being equally probable. To 

 the east of Aasvogel Berg, however, the hills are cut strictly to a 

 plateau which has now been worn into, and the softer beds removed, 

 so that the country is one succession of steep valleys ; yet the crests 

 of the intervening ridges all touch a level sky-line, and occasionally 

 also open flats still occur perched on top of the hills. These latter 

 are very important economically, as the Witteberg rocks are not as 

 a rule pervious to water, and the highly inclined beds of quartzite 

 act like so many pent roofs, down the sides of which the rain-water 

 rushes so impetuously that none is left to sink into the ground and 

 nourish the vegetation that grows upon them ; where these flats 

 occur, since they include the softer rocks as well as the harder 

 quartzites, the rain-water has a chance to sink in, and, as a result, 

 they are covered with grass and luxuriant bush, and below them 

 springs issue. 



When one looks northwards from these hills in the region of 

 Prince Albert, one notices an immense plain and then a ridge of 

 hills ; one can see the two very well from the railway between 

 Prince Albert Boad and Groot Fontein on the Western system. 

 One at once notices that these hills to the north of the plain are all 

 level-topped, or at any rate the summits of the ridges all rise to a 

 certain elevation, no more and seldom less ; this unmistakably 

 indicates that they are remnants of a plain of erosion, as the beds of 

 which they are composed are contorted, and had they not been so 

 cut down they would have formed a series of jagged and irregular 

 hills (Big. 5). The height of the hills is from 3,000 to 3,500 feet, and 



