Deposition of Gold in South Africa. — Czyszkowski. 307 
It is thus that the theory of a lacustrine basin in the Wit- 
watersrand has been readily abandoned and replaced to ad- 
vantage by that of an auriferous marine formation whose 
strata are supposed to extend entirely across southern Africa. 
There is seen to-day in Africa the same condition that ex- 
isted at Bilbao in Spain when the English discovered that 
celebrated deposit. 
Assumed to be an immense bed, 100 meters thick, of pure 
iron ore, it was supposed to extend throughout the country 
like the Cretaceous terrane which contained it. It was 
thought to be unlimited and inexhaustible and he was not 
highly esteemed who thought otherwise. "It is beyond doubt," 
concluded one engineer, "that these ores have been deposited 
by warm springs during the Cretaceous period." 
It was the favorite theory, the theory of the day, and was 
most favorable for future developments ; but unfortunately 
it was false. Our study of this region for the Compagnie de 
Mokta-el-Hadid in 1877, after the examination of other sim- 
ilar but less important deposits of the Mediterranean basin, 
instilled in us the conviction that the iron ore deposit of Bil- 
bao was of later date than the Cretaceous formation in which 
it lay, and that it was probably of Miocene age. 
We published in 1879 an article demonstrating the super- 
ficial and independent origin of this fine ore deposit. It could 
be inferred from that article that the deposit was limited and 
that although important, its exhaustion could be predicted. 
To-day it is almost worked out. 
We published the correct facts regarding the age, origin and 
characteristics of the island of Elba and of various other 
points in the Mediterranean basin. 
Many engineers and geologists have recognized the real ex- 
istence of the great Tertiary supply of iron of which Bilbao, 
Tafna, Elba, Cerro de Hierro (Pedroso) etc., are examples. 
It is by studying all the phenomena and the entire region in 
which they occur that we have the best opportunity for com- 
prehending it. It is not wise to take too close a view of ore 
deposits. An observer stationed at the foot of the Eitl'el tower 
could not give a good account of its form and proportions. 
Placed at a distance, however, he might obtain a very fair idea 
of it. 
