18 STRUCTURE IN PONDOLAND 



lower members of the Cape system, and finally upon 

 rocks of Pre-Cape age, as it is traced northwards from 

 Karroo Poort. We shall see later that this great trans- 

 gression, or unconformable overlap, is of fundamental 

 importance in enabling us to form an idea of the geo- 

 logical history of the Colony, but at present it will be 

 sufficient to say that at least the chief cause of the 

 thinning out of the Cape system is the denudation 

 which took place before and during the deposition of 

 the Dwyka series. 



It has been stated that the folded belt disappears 

 under the sea near the Gualana River, and it would be 

 interesting to find out what becomes of it farther east. 

 It is, of course, impossible to discover the exact state of 

 affairs, but a comparison of the structure of the seaboard 

 of Pondoland with that of the Van Rhyn's Dorp end of 

 the folded belt will give us a clue to it. 



In Pondoland some of the rocks which form the 

 folded belt in the south of the Colony reappear on the 

 coast near the St. John's River, but are very different 

 in certain respects from their condition west of the 

 Gualana River. They are found to be very slightly 

 folded ; the great anticlines of the south and west have 

 no counterpart there, and the greater part of the Cape 

 formation is altogether absent. The rocks emerge from 

 the ocean with a northerly trend, instead of the east 

 and west strike which they have in the south. At St. 

 John's there is a great block of Table Mountain sand- 

 stone, surrounded on all sides by beds belonging to the 

 Karroo formation faulted down against it, but further 

 north-east towards Natal the Dwyka rest unconform- 



