150 CONDITIONS OF DEPOSITION 



partly owing to the strong development of the cleavage, 

 but partly on account of the more uniformly fine-grained 

 nature of the rocks. Few fossils have been found in 

 the Bokkeveld beds south of the Langebergen, probably 

 because those contained in the slates are so much dis- 

 torted by pressure that they are not easily recognisable. 

 In the small synclines of these beds, folded in amongst 

 the Table Mountain series in the Knysna Division, 

 several genera have been obtained ; on the Keurboom's 

 Kiver Orthoceras. Phacops, Orbiculoidea, Leptoccelia, Cho- 

 netes, Spirifer, Nuculites, Bellerophon, Tentaculites and 

 crinoids have been found. Farther west a few charac- 

 teristic species have been obtained from the Bredasdorp, 

 Caledon and Worcester Divisions, but they are usually 

 greatly distorted. 



The distinctly finer grained nature of the Bokkeveld 

 beds south of the Langebergen than to the north of 

 those mountains points to the position of the shore-line 

 of the sea in which they were deposited having crossed 

 South Africa in a general east and west direction to the 

 north of the area now occupied by them. It is not 

 possible to determine the position more closely, for the 

 northern limit of the beds is only seen in the west of 

 Calvinia, and is there an eroded surface of great age ; 

 the denudation which swept away the in-shore portion 

 of the Bokkeveld beds took place in the Pre-Dwyka 

 times, and the greater part of the northern limit is still 

 buried beneath the Karroo formation between the Oor- 

 log's Kloof Eiver west of Calvinia and the submerged 

 south-eastern portion of the folded belt off the south-east 

 coast. 



