TRANSACTIONS OF SECTION C. 403 
time or another, but the various conjectures hitherto put forward have not stood 
the test of time. The best-known attempts to connect the Transvaal with the 
Cape formations are those of Schenck! and Molengraatf.” The suggestion of the 
former was that the lowest Witwatersrand beds represented the base of the 
Table Mountain sandstone, while Dr. Molengraatf thought that the threefold 
sequence of the black reef, dolomite, and Pretoria beds corresponded with the 
three conformable members of the Cape system, thus : 
3. Pretoria Beds = Witteberg Series. 
2. Dolomite Series = Bokkeveld Series. 
1. Black Reef Series = Table Mountain Series. 
The fact, however, that at the Cape the basement beds of the Karroo system 
(viz., the Dwyka series) succeed the Witteberg series conformably, while in the 
Transvaal the Dwyka conglomerate lies unconformably on the Waterberg sand- 
stone, which itself rests unconformably on the Pretoria series, shows clearly that 
neither of these correlations can be maintained. 
The author of the present communication and Dr. Corstorphine in their 
recently published ‘Geology of South Africa’* give reasons for correlating the 
base of the Waterberg sandstone with that of the Table Mountain sandstone. 
The clue to this view was first afforded by the Cango series of the Oudtshoorn 
district in the Cape Colony, which has been shown by the Cape Survey to be older 
than the Table Mountain sandstone. The OCango series contains a dolomitic 
limestone comparable in all respects with the well-known dolomite of the Trans- 
vaal, and it is overlaid by dark slates resembling those of the Pretoria series, and 
underlaid by beds of a quartz-felspar-grit, not unlike the arkose quartzite so often 
found at the base of the black reef series. It-seems therefore more than prob- 
able that the Cango dolomite is of the same age as the Transvaal rock ; and if 
this assumption be true the lowest member of the Cape system (viz., the Table 
Mountain sandstone) can only be represented by the Waterberg sandstone, while 
the two upper fossiliferous members (viz., the Bokkeveld and the Witteberg series) 
are wanting in the Transvaal. 
The Ventersdorp system of the Transvaal, which is continuous into the 
Northern Cape Colony, where it appears as the amygdaloids of the Vaal River, 
and as the melaphyres, quartzites, and quartz porphyries found below the Mecca 
beds in the shafts of the Kimberley diamond mines, is probably represented in the 
Southern Cape Colony by the Cango Conglomerate and the Ibiquas series (in part), 
while the Witwatersrand system is entirely absent at the Cape. 
The scheme of correlation put forward by the author and Dr. Corstorphine is 
then as follows :— 
Southern Cape Colony Northern Cape Colony Transvaal 
Base of the Karroo Base of the Karroo Base of the Karroo 
System System System 
Witteberg Series (missing) ~ (missing) 
Cape Bokkeveld Series ' (missing’) (missing) 
System |Table Mountain Matsap Series Waterberg Sand- 
Series : : stone 
PDs as PLAYIN ODI 
1 A. Schenck, Die geologische Entwickelung Siidafrikas. Petermann’s Mitthetlungen, 
Band 34, 1888, pp. 225-232. . 
2 G. A. F. Molengraaff, Report of the State Geologist of the S.A. Republic for the 
year 1897, Trans. Geol. Soc. S.A., vol. iv. p. 119. Johannesburg, 1898. ; 
The Geology of South Africa, by F. H. Hatch and G. 8. Corstorphine. Macmillan 
and Co., London, 1905, 
DD 
