442 "W. M. DAVIS OBSERVATIONS IN SOUTH AFRICA 



equivalents of the Cape system) still lie horizontal. To the northwest 

 and west the older rocks are disturbed and highlands may well have ex- 

 isted thereabout in Karroo time; but it is also probable that the Karroo 

 basin was inclosed by higher land to the southeast, where the Indian 

 ocean now stretches; for, as has already been pointed out, the oblique 

 stretch of coast, trending northeast-southwest, distinctly bevels off a 

 former greater extension of the continent in that direction. Indeed, in 

 so far as this reconstruction of the physiography of Karroo time is valid, 

 it warrants the comparison of the Karroo strata with the continental 

 deposits now accumulating in the Tarim basin of eastern Turkestan or 

 with the less distinctly inclosed deposits of western Turkestan. The 

 change from that time to the present must therefore involve a consider- 

 able reduction of continental area. It may be briefly pointed out that 

 the present relation of the Karroo formation in the Veld to so much of 

 its original surroundings as are now visible is such as would obtain in a 

 rather late stage of the development of a great continental basin, when 

 the inclosing highlands and the accumulated basin deposits are both cut 

 across by a nearly level plain of erosion, which passes somewhat below the 

 uppermost of the basin strata, and hence all the more below the tops of 

 the inclosing highlands; but so great a part of the rim of the Karroo 

 basin is now lost that speculation about it can not lead to any definite 

 conclusion. 



Still further, the continent seems to have been larger than now when 

 the Cape and the Karroo systems were deformed as well as when they 

 were accumulating. The most manifest evidence of this statement is to 

 be found along the oblique northeast-southwest stretch of the coast in 

 eastern Cape Colony and southern Natal. Here the sea cuts off the east- 

 ern ends of several east-and-west members of the Cape Colony ranges, 

 part of the relatively undisturbed basin sediments of the Karroo system, 

 and the southern end of the north-and-south structures of Natal. The 

 rest of the coast of Natal as well as the southern coast of Cape Colony 

 present less apparent, but hardly less certain, evidence of a former ex- 

 tension seaward, for their structures are repeatedly truncated by the sea 

 in such a fashion as to show a loss of land area. On the southwest the 

 general increase in altitude of the Table Mountain sandstone, as one 

 proceeds from the north-south Cedarbergen range toward the Atlantic, 

 makes it very improbable that the land terminated at the present coast- 

 line when the deformations of the Cape system took place. 



Thus it appears that possibly during the time of accumulation of the 

 formations of the Cape system, probably during the time of accumula- 

 tion of the formations of the Karroo system, and certainly during and 



