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GOLD SAND OF AFRICA AND ASIA. 
PROOFS OF DILUVIAL ACTION IN AFRICA AND ASIA. 
The gold that occurs so largely in various parts of Africa is 
chiefly found, like that last spoken of, in the state of small rolled 
grains disseminated through diluvial sand and gravel; so also is the 
tin, which is so abundant in the peninsula of Malacca, and in Banca, 
and other islands adjacent to Sumatra, being simply diluvial or stream 
tin, like that of the gravel of Cornwall. 
In Hindoostan, near Bombay, agates and onyx stones are col¬ 
lected as pebbles from diluvial gravel beds; whilst many of the plains 
in the interior of India contain amidst their gravel rolled pebbles of 
copper ore, in quantity sufficient to send large supplies of malachite 
to the eastern markets. The greater part of the diamonds also of 
India, as well as of South America, and the precious stones of Ceylon, 
are found dispersed in the state of small sand and pebbles through 
diluvial gravel. In the same kind of gravel also are found the topaz 
pebbles of Cairn Gorm, in Scotland. 
The erroneous idea of the old mineralogists, that the sand of all 
rivers in the world contains gold, is true only of those which flow 
through countries that are strewed with the wreck of mountains, 
through which gold had been once disseminated, i. e. of primitive 
and transition rocks ; and as most great rivers of the world have their 
origin in rocks of this kind, the very general dispersion of grains of 
gold along their course adds another fact to the many I have already 
advanced, to show the effects of diluvial action to be co-extensive 
with the surface of the whole earth. 
