It suggests a deposit
in some ancient lagoon, alternately fresh and salt. A hard fissile slate
of purple colour is based upon the ground-rock of grey granite; there is
also a modern clay-slate, which lies unconformably to the older, and
through it the great veins of gneiss and quartz seem to pass. The alluvial
detritus, which fills up the valleys to their present level, is formed by
the diluvium of the hills: in parts these bottoms show strata, from one to
three feet thick, of water-rolled pebbles bedded in clay. Here and there
the couch must be a hundred feet deep, and the whole should be raised for
washing by machinery. These strata were apparently deposited in a lagoon
of more modern date.
The gold is sometimes visible in the gneiss; and I have seen pieces whose
surface is dotted with yellow spots resembling pyrites. It is often in the
form of spangles called float-gold and flour-gold. Select specimens have
yielded upwards of eight ounces to the ton. If the blanketings and first
tailings be properly treated, it should afford an average of at least an
ounce and a half per ton. Treating a hundred tons a day gives a sum of
30,000 per annum; and, assuming 6_l_.
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