540 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



just at a bend or shoulder, where a glacier, descending from the 

 northward, would press with the greatest force before turning off to 

 the watershed of the Koraani or Inquobo just mentioned. But 

 there are many places where these rounded or dome-shaped rocks 

 are to be found. Thus among these same mountains, near where 

 the Zwart Kei passes through, they are found on both sides of a 

 gorge forming an outlet to an auxiliary branch of that river, near a 

 farm occupied by Mr. Lenard, and through which ia an outlet to a 

 basin as large as, although more irregular in shape than, those of 

 Schaap Kraal and the Bongolo (see below). Of this outlet I have sent 

 a sketch (Y). Here the rocks are perfectly rounded off to the height 

 of several hundred feet ; it is impossible to imagine how water alone 

 could have produced such an effect. Eocks with similar features 

 occur in another precipitous glen, forming the outlet of a large 

 valley-basin called Schaap-Kraal Hoek (vide infra), near Tarkastad. 

 In this case, on the one side all the rocks are smoothed and rounded, 

 while on the opposite side are beds of unstratified drift intermixed 

 with immense angular boulders. And here, again, we find a portion 

 of this boulder- clay resting upon the same kind of sandstone, with 

 its imbedded boulders and fragments of rock, as at the Bongolo 

 Neck. 



Another notable instance of these dome-shaped rocks I noticed 

 on the road from the Rhenosterberg to Cradock. They were outliers, 

 forming smaU, rounded, bubble-like hiUs in the middle of a wide 

 flat valley some miles broad. 



Basin-like valleys, their moraines, striae, ^c. ; Schaap-Kraal Hoek. 

 — Another remarkable feature in the denudation consists of so-called 

 flats, but really basins, which seem to have been scooped out of the 

 horizontal strata. It is very difficult to understand how they could 

 have been so excavated by the simple agency of water, or the ordi- 

 nary atmospheric influences of any climate except an antarctic one. 

 Thus a place before mentioned, Schaap-Kraal Hoek, is an elevated 

 valley some 12 miles long and 6 or 8 broad ; it is surrounded on 

 every side by a continuous range of mountains. The outer face of 

 all these mountains is exceedingly abrupt and precipitous, whereas 

 within the basin no precipitous rocks are to be seen ; the sides are 

 all smoothed off, gradually sloping from the highest ridge towards 

 the centre, as if the strata that had once filled the intervening space 

 had been scoured out. The inner face of the highest rocks, columnar 

 on the outer precipices, shows lines of stratification. (See section, 

 fig. 15.) 



As the elevation of this vaUey is so near the level of the original 

 plateau, without any inlet through which water could have fiowed, 

 one cannot imagine but that the denuding power must have been 

 some such agent as ice that accumulated within the basin itself. 

 Before the eroding of the outlet described above, a far more 

 ancient one existed where the road now passes towards Buissen's 

 Spruit, a branch of the Eland's Eiver, and at the extremity opposite 

 to the present outlet. At both these outlets, where they debouch 

 into the lower country, the mountain-sides are loaded, to the height 



