THK KAItliOO SYSTEM 175 



it is again seen filling old valleys cut out of the Matsap 

 series near Kuis on the Molopo. These exposures in- 

 dicate the existence of an outlier, perhaps over 10,000 

 square -miles in area, north of the Orange Eiver and 

 west of the Korannabergen. The outlier is continued 

 in German South- West Africa and in the Bechuanaland 

 Protectorate'. Though the base of the tillite has been 

 seen at several spots where it rests upon granite and 

 shales and sandstones of the Zwart Modder series, a 

 striated floor has not been found, doubtless owing to 

 the nature of the older rock, which is not favourable 

 for the retention of striae. Between Van Wyk's Vlei 

 (Carnarvon) and the Langberg (Calvinia), a distance of 

 150 miles, the boundary of the Dwyka has not been 

 traced. In Bushmanland the tillite rests upon granite 

 and gneiss (Plate XII.), and farther south upon the 

 Ibiquas beds without being in the least affected by the 

 great dislocation which separates the granite from the 

 latter. South and west of Uithoek the much-denuded 

 Table Mountain sandstone intervenes between the 

 Ibiquas and the Dwyka, and higher and higher beds are 

 seen to the south ; south of the Oorlog's Kloof Eiver 

 the Bokkeveld beds appear. Fifty miles farther south 

 the Dwyka rests upon the basal beds of the Witteberg 

 series, and the latter formation continually thickens as 

 Karroo Poort is approached. At only two or three spots 

 along this part of the boundary has the actual contact 

 been seen, and although the surface of the Witteberg 

 quartzites is striated at those places there are so many 

 slickensided surfaces in the same rocks, produced by 

 the bending and consequent slipping of one layer over 



