THE GEOLOGICAL HISTORY OF THE COLONY 451 



than their remnants are found to-day, but as they are 

 distinctly in-shore deposits, as opposed to those formed 

 under deep-sea conditions, they probably never stretched 

 far inland beyond their outcrops in Pondoland. We 

 have as yet no sign of a passage from the Uitenhage 

 into the Umzamba series, but negative evidence on 

 such a point is worthless under the circumstances ; we 

 cannot, therefore, say whether the ocean retreated and 

 returned, or whether a conformable group of beds, from 

 the Uitenhage to the Umzamba series, once existed in 

 or near the south-east limit of the Colony. 



The course of events north of the watershed in the 

 country drained by the Orange Kiver is difficult to 

 decipher; the mountain building which produced the 

 southern and western ranges did not affect the north 

 of the Colony, and no equivalents of the Uitenhage 

 beds are known to exist in that region. 



The earliest recognisable stage in the erosion of the 

 Drakensberg is represented by a peneplain in Barkly 

 East standing at an altitude of 8,000 feet above sea 

 level. This must have been cut by the head-waters of 

 the Orange River, when the continent stood at a much 

 lower level than now, and long before the southern 

 escarpment of the Drakensberg had reached its present 

 position. Upon elevation this plateau was dissected 

 and a peneplain formed at the 6,000 foot level, the 

 terrace being visible over the greater part of the Storm- 

 berg region. 1 It apparently extended north-westwards 

 with a very gentle slope in that direction over the 

 Orange Eiver Colony into Griqualand West, where it is 



i Du Toit, T. S. A. P. S., vol. xvi., p. 53, 1905. 

 29 * 



