1872.. TTLRTCH TIN-ORE DISCOVERIES IN NEAV SOUTH WALES. 7
Companies on the opposite side of the river similar stanniferous
quartz-veins and dykes had been discovered, the conclusion I came
to is, that the granite mass, as a whole, represents one of the
so-called " Stocks " or " Stockworks " similar to those of Saxony and
Bohemia, but of incomparably greater size and richness.
As far as could be seen in the small workings of the Elsmore
Company on several of the quartz-veins and dykes, the dip of the
latter is rather steep, and the walls pretty well defined, but thick-
ness irregular ; thin flat veins join in occasionally. The deepest
shaft sunk on one of the quartz-veins was about 60 ft. ; and the tin-
ore occurred in irregular thin veins, and often beautifully crystal-
lized in druse-cavities. On examining the spoil-heap round this
shaft, I discovered lumps of a ferruginous clayey substance full of
thin light-green and yellow hexagonal prisms of beryl, associated
with larger quartz-crystals. I also observed beryl on crystallized
cassiterite specimens, its fragile prisms, generally not thicker
than a stout pin, and up to an inch in length, interlaced between
the tin-ore crystals. Of other minerals, I found in the stuff ex-
cavated from one of the dykes frequently patches of arsenical
pyrites, and more rarely grains of copper pyrites, the former
generally containing imbedded crystals of tin-ore. From another
part of the ground the manager preserved a large piece of fine rock-
crystal, which also enclosed small crystals of the ore. Wolfram has
been found at several places forming nests in the granite, but not
in association with cassiterite. Touching the latter itself, it is
mostly of a pitch-black colour, occasionally translucent brown and
hyacinth-red, and from some places greenish with a very pretty play
of rays of red and yellow colour through it. Its crystalline form is
rather simple as regards pyramidal planes ; the prism is generally,
however, highly modified. Twins like those from the Schlaggen-
wald mines are very abundant ; and crystals perfectly developed all
round, both twins and simple ones, the latter with twelve-sided prism
and one pyramid, are not rare amongst the ore washed from the drift.
As regards the drift, it is very rich, and consists of recent granite
detritus, from 6 in. to 2 ft. thick, spread all over the range, and of an
older, probably Pliocene Tertiary cemented gravel of several feet
thickness and mainly composed of waterworn pebbles and boulders
of quartz (frequently rock-crystal and cairngorm), hard granite and
hornstone, capping the top of the range, and dipping most likely,
analogous to the older gold-drifts at other places, beneath the basalt
adjoining (see sketch section, fig. 1).
Fig. 1. — Sketch section across the becl of the Maeintyre River.
Macinfcyve River.