THE CAPE SYSTEM 131 



intervals the ground is extraordinarily rough and difficult 

 to traverse. The moderate effects of weathering along 

 joints are familiar to every one who has been to the top 

 of Table Mountain, where there are many curiously 

 shaped knobs and pinnacles due to this cause combined 

 with the unequal weathering of the surface. On the 

 eastern slope of the Cederbergen, below Sneeuw Kop, 

 on which a beacon of the geodetic survey stands, the 

 surface of the hill is extremely cut up by these eroded 

 joints. There are two main sets of joints on that slope, 

 roughly parallel and at right angles to the strike of 

 the beds, and a third group is sometimes developed. 

 Weathering and erosion have gone on to such an extent 

 that the mountain side is covered with an intricate mass 

 of vertical walls and pinnacles of rock from five to forty 

 feet high. Although such a fine development of joint 

 weathering is not often met with, similar features are 

 common on all the folded mountains made of the Table 

 Mountain beds. 



A very frequent feature in the sandstones of this 

 group is the occurrence of rounded pebbles of white 

 quartz up to three inches in length, though they are 

 rarely more than an inch long. They are usually 

 sparsely scattered through the rock, rarely in thin layers 

 a few feet long. Conglomerates are of restricted occur- 

 rence, but they are found at Pikenier's Kloof, Baboon 

 Point and a few other localities in the west, and in the 

 Knysna and Uniondale Districts. Most of the pebbles 

 are of quartz and quartzite. Granites and quartz por- 

 phyries have been found in the small outliers of Klap- 

 muts Hill and Joostenberg, as well as at Baboon Point. 



