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. 

 a. Basalt. 6. Older Drift. c Granite. 



