12 THE KARROO 



The outlines of the northern ranges made of the Pre- 

 Cape rocks are usually soft and rounded, probably be- 

 cause the agency which moulded their surfaces was the 

 southward moving ice of Dwyka times, but, as will be 

 pointed out in a later chapter, the remarkably even sky- 

 lines of many of the ridges made of folded rocks and the 

 flat plateau of the Kaap, cut alike through hard and soft 

 rocks, are probably due to a much later stage of denuda- 

 tion. 



South of Prieska and Kenhardt lie the wide plains cut 

 in the Karroo beds, broken only by table-shaped or coni- 

 cal hills due to the occurrence of the hard sandstones 

 of the Beaufort series or to the presence of sheets of 

 dolerite intercalated with the softer sedimentary rocks 

 and by rough country formed by sheets and dykes of 

 dolerite. 



The Karroo beds in the greater part of the plateau- 

 region have a synclinal arrangement ; to the north of 

 the main watershed they dip south or south-east, to the 

 south of it in the opposite directions ; the inclination is 

 very slight, but as it is continued for many miles the 

 effect is to bring in a great thickness of beds, though the 

 surface of the country only rises 2,000 or 3,000 feet ex- 

 cept towards the Basutoland border, where there is an 

 additional thickness of some 7,000 feet of the Stormberg 

 series. 



The Karroo area is often likened to a basin, but the 

 structure of the southern edge of the basin is very differ- 

 ent from that of the northern, as its position is due to 

 folding which took place after the deposition of a con- 

 siderable part of the Karroo system, while the northern 



