Deposition of Gold in Smith Africa. — Czyszkowski. 315 
Triassic age. They do not appear to have been folded, but 
eruptive rocks and a sort of breccia or subterranean moraine 
(moraine interne) which contains the diamonds of the Cape 
have penetrated it at several points. 
The gold advent of South Africa affected all formations 
earlier than the Karoo. It is thus later than the Carbonifer- 
ous limestone and certain diabases. It appears to have be- 
longed to the great Hercynian [from Carboniferous to Per- 
mian] age of the deposition of metals, which also gave rise to 
the rich veins of Australia. That all the strata covered by 
the Karoo have to-day practically the same general appear- 
ance as at the advent of the gold is indicated by the fact that 
the Karoo has remained horizontal and has not been folded. 
We believe that the gold was deposited at a period when the 
strata of the Cape formation were in an undulating position 
approximately horizontal, while that of Swaziland was on 
the contrary almost vertical. 
From the above considerations it follows that thalwegs and 
metalliferous "niveaux" would have been produced in the first 
formation and bed-veins or intercalated masses like those of 
RioTinto in Spain, in the second. And this is what we find in 
the districts of the Witwatersrand, of "de Kaap" and Lyden- 
burg. It should be stated, however, that after the formation 
of the auriferous beds their horizontal position was disturbed 
at some points as a consequence of fractures and orogenic 
movements as well as by the advent of dykes of green rock 
which have altered the position of the gold-bearing formation. 
Deposits of Witwatersrand. The terrane enclosing it,, reefs 
unit origin of ///<■ /utter. 
Let us examine the Witwatersrand deposits. Taking a 
hasty glance over this entire gold region we sec several meters 
north from Johannesburg granite and gneiss forming an east 
and west ridge between this village and Pretoria. Aboul 20 
kilometers toward the south the granite reappears in the 
Orange Free State. It is between these two granite ridges 
that we find the gold bearing formation composed of strata 
of sandstone, quartzyte, schist and conglomerate comparable 
to the ( 'ape formation and believed to be of Devonian age. 
The dolomyte formation, winch is assigned to the Lower Car- 
boniferous, lies unconformable above the Devonian rocks and 
