PRK-CAPE ROCKS OF THE NORTH OF THE COLONY 111 



remnant of the Table Mountain series, it rests on the 

 greatly folded Matsap beds which are in places 10,000 

 feet thick at least. Now this folding of the Matsap beds 

 cannot have taken place at the surface ; when they were 

 being folded they must have been covered by some 

 considerable thickness of rock since removed, and they 

 themselves were denuded away over large areas in Pre- 

 Dwyka and Dwyka times. If, then, the Matsap beds be- 

 long to the Cape system these 10,000 feet of rock in the 

 north must have been deposited and then folded under 

 the pressure of superincumbent strata, and a very great 

 amount of denudation must have taken place, while the 

 Cape system and the Dwyka, together less than 12,000 

 feet thick, were being deposited in the south. The im- 

 probability of this having been the case invalidates the 

 correlation of, the Matsap and the Table Mountain series, 

 and justifies the placing of the former with the Pre-Cape 

 formations. 



2. THE ZWART MODDER SERIES. l 

 On the western side of Gordonia a group of sand- 

 stones, quartzites and shales is found lying nearly 

 horizontally on the granite and unconformably covered 

 by the Dwyka. These beds extend from Aries to beyond 

 Kietfontein, a distance of about 100 miles, though covered 

 over long stretches by the Dwyka, and they undoubtedly 

 occupy a wide area in German South-West Africa ; 

 eastward they disappear under the sand of the Kalahari. 

 The basal shales and sandstones are usually reddish, 

 but the highest beds seen are dark blue or grey micaceous 



1 G. C., xii., p. 43. 



