THE GEOLOGICAL HISTORY OF THE COLONY 431 



Witteberg beds, and they are usually found in frag- 

 ments, bits of stems without leaves or other organs, 

 and these fragments probably drifted far before becom- 

 ing waterlogged. In the Eastern Province some beds 

 are largely made up of compressed coaly-looking stems. 

 Current bedding and ripple marks are very usual phe- 

 nomena in the Witteberg series. In the south of the 

 Colony the Witteberg period was brought to an end by 

 the deposition of the green shales and mudstones of the 

 Lower Dwyka beds, and no physical break or uncon- 

 formity separates the two groups of rock. Deposition 

 must have gone on continuously in the south of the 

 Colony while the great change of climate took place 

 that caused the glaciation of the country to the north 

 of the Karroo. 



While the deposition of sediments of various kinds 

 went on uninterruptedly in the southern districts from 

 the time of the Table Mountain series till far on in 

 that of the Karroo formation, a rising of the floor began 

 in the country north of the thirty-third parallel at some 

 time during the Bokkeveld or Witteberg periods ; for 

 both in the west and east of the Colony north of that 

 parallel of latitude an unconformity separates the lowest 

 beds of the Dwyka series from the Cape formation. 

 This rising of the land relatively to the water level must 

 have taken place very gradually, as there is no strong 

 discordance between the newer and older rocks. The 

 Witteberg and Bokkeveld beds become gradually thinner 

 and thinner northwards owing to the removal of a greater 

 thickness of the beds in that direction during Pre-Dwyka 

 times. 



