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GOLD.
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121
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of Upper Assam, and were supplied with ample funds for carrying out their investigations.
From
an abstract of their reports, by Dr. T. Oldham, late Superintendent of
the Geological Survey of India, I quote the following :*β
Gold
was obtained in the Brahmaputra at Parghat, above Sudya, and in several
tributaries, Noa-Dehing, Dihong, and Hookong. " The spots selected by
the natives are those salient angles or reaches of the river where the
alluvial deposits, cut away by the stream from the opposite bank, are
partially redeposited, after having undergone the sifting action of the
current."
The
gold " is derived from the crystalline rocks in the first instance, but
only becomes sufficiently concentrated to render it worth working in
the alluvium, after this alluvium has undergone repeated washings in
the river current, by being successfully cut away, washed, and
re-deposited as the river changes its course."
The
Dihong river, from the hills to the north, " yielded gold in
considerable quantity, from its junction with the Brahmaputra to about
half-way between that stream and the hills." 5f tons of gravel yielded
90 grains of gold = i6i grs. per ton. " This stream is considered by
the natives to be the richest in Assam."
The
apparatus used in these investigations were a Californian cradle worked
by four men, and which was found to give the largest daily yield per
man; and a Singpho washing dish worked by one washer and one assistant.
No. 1. Gold from Brahmaputra yielded 88'28l per cent, pure gold
No. 2. Noa Dehing ,, 93'880 β ,,
Dihong ,, 90-234 β
Hookong ,, 86-588 ,, ,,
Burmah.βThe following facts are taken from a
* " Mem. Geol. Survey of India," vol. i. p. 90.
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