466 Transactions of the South African Philosophical Society. 



Hatch, F. H. ''A Geological Survey of the Witwatersrand and 

 other Districts in the Southern Transvaal. Q. J. G. S., liv., 

 1898, pp. 73-100, with a map and 5 figures. 



The rocks are divided into three groups, which are sub- 

 divided as follows : — 



Karoo System. Coal - bearing beds of Yereeniging and 

 Boksburg. 



Magaliesberg (Pretoria Beds of Molen- 

 graaff) and Gatsrand series (Klip Eiver 

 i series of Penning). 

 Upper Beds 4 Dolomite. 



Black Eeef series (Boschrand series of 

 Molengraaff) and Klipriversburg amygda- 

 loids (lavas). 



CD 

 CO 



CO 



CD 

 & 



o 



/ Witwatersrand Beds. 



Hospital Hill series '(Schistose Eocks of 



'Lower Beds ~ Afford. Lower quartzite and shale group 



of Gibson. Alte Schieferformation of 



\ Molengraaff. 



Archaean. — Acid and basic igneous rocks, with some meta- 



morphic schists. 



It is held probable that the Witwatersrand Beds are the 

 counterpart of the Cape Table Mountain Sandstone. 



The various groups of the rocks are described, and an 

 account is given of the principal faults of the district. 



A. W. E. 



Gibson, W. " The Age of the Eand Beds." Geol. Mag., New 

 Series, Dec. iv., vol. iv., No. 12, 1897, pp. 548-550. 



Observations have shown that in the Cape Colony the Karoo 

 Beds have been involved in the disturbances affecting the Table 

 Mountain Sandstone, and overlying Palaeozoic rocks. In the 

 Transvaal the Karoo Beds are undisturbed when found near the 

 Palaeozoic Beds. It is usual to regard the Eand Beds as 

 belonging to the Table Mountain Sandstone, but it seems 



probable that they are of pre-Table Mountain Sandstone age, as 

 are the Malmesbury Beds of the Colony. 



A. W. E. 



