Deposition of Gold in Smith Africa. — Czyszkowski. 309 
This theory seems to as as questionable as that which has 
for a long time passed current as an explanation of the for- 
mation of beds containing coal, and which consists in suppos- 
ing regular rising and falling movements of the earth's crust 
in order to account for the formation of alternating beds of 
coal, of schist and of sandstone. 
M. Jules Gamier also supposes that the precipitation of 
the gold was contemporaneous with the conglomerate but 
thinks that the beds were formed in an inclined position like 
marine deltas and not horizontally. 
We do not see any necessity for creating a new theory to ex- 
plain the Transvaal deposits. Simple circulation of mineral 
waters in the earth's crust, similar to that which has taken 
place in all known metalliferous districts, will explain all the 
various deposits of South Africa. One single but very im- 
portant method of gold deposition has, in our opinion, been 
able to form them all, and that is what we shall attempt to 
demonstrate. Let us mention in the first place that we find 
the gold associated with silica and pyrite in all the auriferous 
regions of Africa. Everywhere the ore lias the condition of 
quartz and auriferous pyrites. 
It may be said that this is not a proof of one single origin 
for the gold ; but if it is not a proof it is at least an argu- 
ment. If there had been successive supplies of gold during 
one or several geological periods it would indeed be extraor- 
dinary to find the phenomenon reproduced with such uniform- 
ity and to have seen such constancy in the composition of 
the mineral springs which brought it out and deposited it. 
This then is our first argument in favor of one single sup- 
ply subsequent to the enclosing terranes : uniformity of com- 
position of the ore. 
Origin of mineral waters. Circulation of waters, both surface 
a ml deep-seated. Thalwegs and metalliferous strata (niveaux). 
In order to be thoroughly understood it is necessary to say 
a few words regarding the mineral springs to which we owe 
the deposition of metalliferous beds, to speak of their circu- 
lation in the pervious strata of the earth and of the influence 
of the position and characteristics of the \)t'i\± on the form 
and nature of the deposits. 
