166 
EOLIAN GEOLOGY 
kind. Its adequate explanation constitutes a fairy chapter of its 
own. 
In view of these several considerations alone there appears to 
be, after the disturbances of the World War shall have passed, 
little prospect of any immediate or appreciable falling off in the 
world’s supplies of gold. On the other hand, all indications are 
for vast increases. „ 
Keyes. 
Elutriation of Diamonds by the Winds. Mining of precious 
stones by means of the winds is something new in the winning of 
wealth from Earth. Yet the method is a natural process, closely 
akin to the elutriation of gold by hydrolic means, and is a process 
of common practice in the chemical laboratory. On the Namaqua 
Coast of German Southwest Africa diamonds are recovered from 
the sands of that verdureless and inhospitable desert, where they 
are brought down to the sea by the intermittent streams, both 
ancient and modern. 
Since the stones exhibit virtually no wear it is taken as evidence 
that they are not transported far from their source. This fact 
leads those who associate the gem with the volcanic rock called 
kimberlite, to look for mother pipe which fancy longs should be 
somewhere near. Search for such kimberlite pipes is amply re¬ 
corded; but unexpectedly the rock is found to be quite barren of 
stones. Inasmuch as it is quite manifest that the coast region has 
undergone prodigious erosion, so that thousands of feet of the 
original pipe are removed it seems logical to assume that the rea¬ 
son why the pipes are unproductive is the probability that denuda¬ 
tion has reached below the diamond-bearing levels. 
The eolian elutriation of diamonds from the desert sands is thus 
described by Mr. J. W. Finch,^ who recently especially studied 
these gem-fields. “The two principal oldest river channels crossed 
the region just south of the Pomona area. From the latter dia¬ 
monds have been distributed by two transverse, second-period 
streams, one of which entered Elizabeth Bay. In the latter region 
a later river, of a third period, redistributing diamondiferous 
gravels of the two former periods, entered the sea at approxi¬ 
mately the same point. The rich conglomerates within the Pomo¬ 
na area are a concentration of diamonds by an old river of the 
1 Eng. and Min. Jour., Vol. CXIII, p. 318. 1922. 
