178) 



CHAPTEK XIX. 



Notes on Sources op Eock for the Manufacture of Stone 



Implements. 



By A. L. DU ToiT, of the Cape Geological Survey. 



The distribution of the implements is in a number of cases closely 

 connected with certain geological horizons and outcrops of rocks. 

 In many cases, where there was no suitable rock close at hand, 

 their makers must have travelled specially, but small distances, 

 usually, however, to obtain suitable material for the manufacture 

 of implements. 



For example, in the Western and Southern (Ceres and Tanqua) 

 Karroo the hard chert band at the top of the Dwyka shales has 

 been the most important source, and all along its outcrop — especially 

 at Beuke's Fontein — there are numerous flakes and implements, while 

 artefacts of this light grey chert have been carried many miles to the 

 N.E. into the Eoggeveld and Klein Eoggeveld. In this case the 

 rock chosen is extremely suitable for the purpose ; moreover, until 

 one comes right up to the edge of the Eoggeveld there is no other 

 material available, for the lydianite, so commonly used, is only found 

 accompanying the Karroo dolerites (here appearing in the escarp- 

 ment near Sunderland). 



This material was also carried into the mountains of the Cold 

 Bokkeveld. 



In the north of Cape Colony, owing to the variety of the forma- 

 tion, there was perhaps more choice ; but sometimes the material 

 was not quite suitable for working. Around Plessis Kop, &c. (N. of 

 Vryburg), in a flat area of amygdaloidal diabase, the small im- 

 plements are made of bits of agate (weathered out of these vol 

 canic rocks), while many are made of white quartz obtainable a 

 little to the north. The larger implements are of diabase. In 

 northern Mafeking and Vryburg, where there is much sand, the 



