High-level Gravels of the Gape. 



49' 



however, took on more than they could satisfactorily accomplish ; 

 for instance, above Commandant's Drift on the Kammanassie, the 

 river of that name has sent a side streamlet that has tapped the 

 Long Kloof east of the farm Molen Eiver (Fig. 2) ; the water pours 

 out over a fine waterfall into a deep pool, and is carried out in 

 furrows; after the gorge had been first formed, the running water cut' 

 down to extremely hard quartzite, which it has only been able to 

 wear away very slowly ; hence the drainage area behind the water- 

 fall has remained at a minimum level for a very long time, and has 

 thus been made into a plain of erosion exactly as the higher plain,. 



Fig. 3. 



Birds'-eye view of the gravel- capped bevel in the Kammanassie Valley 

 opposite Commando Kraal. 



of which a few flat-topped hills attest the former existence, was cut 

 down. The Long Kloof, unfortunately, has not yet been geologi- 

 cally surveyed to any great extent, and a good deal more about these 

 river-systems will be learnt when it is done. The gravels in the 

 Kammanassie Valley about Commandant's Drift, and lower down, 

 are coarser than round Uniondale, and are heavily charged with 

 iron (Fig. 3). 



In the upper Oliphant's Eiver we have another area where the 

 gravels can be very well seen. Standing on any high point in the 

 rim of the basin one notices a shelf cut in the mountains, which runs 

 uninterruptedly and at exactly the same level all round. It looks as 

 if it were the eroded edge of a lake whose waters had now been 



