164 Walcot Oibson — Palceozoic Rocks of South Africa. 



inversion. Their exact position in the sequence is somewliat 

 doubtful, but in the account of the report for 1898 it would ap[)ear 

 that these Cango rocks are to be regarded as being older than the 

 Table Mountain Sandstone, but newer than the Malmesbury Beds. 

 Mr. E. J. Dunn regarded them as the equivalents of his Namaqua- 

 land schists ; that is, as belonging to a formation older than the 

 Malmesbury schists. The task of unravelling the stratigraphy of 

 this complicated region remains to be worked out when better maps 

 are available. At present it is very unsatisfactory, especially when 

 these Cango rocks appear to bear considerable resemblances to some 

 of the deposits of the Transvaal Colony, which are considered 

 by Dr. Molengraafif to be the equivalents of the Table Mountain 

 Sandstone and Bokkeveld Beds. 



Between the areas occupied by these older rocks in the southern 

 provinces and the Prieska division (described in the report for 1899), 

 south of the Orange River, a tract of country over 200 miles wide 

 intervenes, of which the geology has not been reinvestigated. 

 A large portion of this area is occupied by the Karroo formation, 

 but the older rocks emerge from beneath it along the edges of the 

 Karroo basin and have not yet been examined by the members of 

 the Cape Geological Commission along their whole length. So far 

 as Messrs. Eogers and Schwarz have examined the formations 

 in the district of Prieska, they have determined the following 

 descending sequence, naming the rock groups in accordance with 

 the nomenclature adopted by Stow for the regions north of the 

 Orange Eiver in Griqualand West. 



Table of Formations in the Prieska District.^ 



G-laoial Conglomerate and Shales A coarse conglomerate resembling a grunde 



moraine. Overlying shales, carbonaceous 

 and tbin-bedded. 

 Great Unconformity. 



Matsap Series ... ... ... Quartzites and grits with pebbles of jasper 



rock. A sheared conglomerate at the 

 base containing fragments of Griqua Town 

 Series. 

 TTneonformity. 



Griqua Town Series Magnetic jasper rocks. 



Campbell Rand Series ... ... Limestones and quartzites. 



Keis Series ... ... ... ... Quartzites and mica-schists. 



A granitic series is found in connection with the Keis group of 

 rocks, but the relation of the two is uncertain. Messrs. Rogers and 

 Schwarz state (p. 75 in report for 1899) : " although the conclusion 

 is mostly supported by negative evidence, it is pi'obable that the 

 whole granitic series was intruded among the Keis rocks, and that 

 its gneissose structure was impressed upon it at the time when the 

 dominant strike was given to the sedimentaries." The Campbell 

 Rand and Griqua Town Series constitute a great mass of rooks, 

 forming the Doornbergen and other areas in the district. Together 

 with the Keis Series they appear to form an ascending sequence 



1 Report for 1899, Cape Geological Commission. 



