THE KARROO SYSTEM 191 



of the Winkelhaak Kiver in the Cold Bokkeveld, at 

 Quarrie Kloof between Touw's Kiver and Constable 

 stations, and at four other places in that neighbourhood. 

 One of them is in Dobbel Aar's Kloof, about thirty miles 

 south of the Quarrie Kloof outlier. All these outliers 

 are boat-shaped synclines, with the exception of the first, 

 which is bounded on one side by a fault. 



Between Karroo Poort and Grahamstown the outcrops 

 of the Dwyka are repeated by folding, but their distri- 

 bution east of Steytlerville is not known in detail. 



The question of the presence of coal in the Dwyka 

 shales beneath the Karroo is one that must be briefly 

 touched upon. Mr. Dunn in 1886 l came to the conclu- 

 sion that the carbonaceous shales of the White band 

 would contain coal at certain points in the Karroo where 

 they are hidden by a great thickness of Ecca and Beau- 

 fort beds. In 1899, 2 when he found that the Vereenig- 

 ing coal rested upon the Dwyka conglomerate, he 

 naturally considered his case for the existence of sub- 

 Karroo coal greatly strengthened. The facts, however, 

 are that the black shales taken at various points along 

 an outcrop of about 1,000 miles round the edge of the 

 present basin of the Karroo show remarkably uniform 

 characters and that their carbon content is invariably 

 low. Mr. Dunn supposed that the vegetable material 

 would be swept in towards the centre of the basin and 

 that' the shale would be replaced by coal as the centre 



1 Dunn, E. J., " Keport on a Supposed Extensive Deposit of Coal Under- 

 lying the Central Districts of the Colony," Parl. Hep., G. 8, Cape Town, 

 1886. 



2 Dunn, E. J., " Notes on the Dwyka Coal- Measures at Vereeniging, 

 Transvaal," T. S. A. P. fif., xi., p. 67, 1900. 



