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| Keywords: The Quarterly journal of the Geological Society of London (13368815083).jpg 1872 TTLRTCH TIN-ORE DISCOVERIES IN NEAV SOUTH WALES 7 <br> Companies on the opposite side of the river similar stanniferous <br> quartz-veins and dykes had been discovered the conclusion I came <br> to is that the granite mass as a whole represents one of the <br> so-called Stocks or Stockworks similar to those of Saxony and <br> Bohemia but of incomparably greater size and richness <br> As far as could be seen in the small workings of the Elsmore <br> Company on several of the quartz-veins and dykes the dip of the <br> latter is rather steep and the walls pretty well defined but thick- <br> ness irregular ; thin flat veins join in occasionally The deepest <br> shaft sunk on one of the quartz-veins was about 60 ft ; and the tin- <br> ore occurred in irregular thin veins and often beautifully crystal- <br> lized in druse-cavities On examining the spoil-heap round this <br> shaft I discovered lumps of a ferruginous clayey substance full of <br> thin light-green and yellow hexagonal prisms of beryl associated <br> with larger quartz-crystals I also observed beryl on crystallized <br> cassiterite specimens its fragile prisms generally not thicker <br> than a stout pin and up to an inch in length interlaced between <br> the tin-ore crystals Of other minerals I found in the stuff ex- <br> cavated from one of the dykes frequently patches of arsenical <br> pyrites and more rarely grains of copper pyrites the former <br> generally containing imbedded crystals of tin-ore From another <br> part of the ground the manager preserved a large piece of fine rock- <br> crystal which also enclosed small crystals of the ore Wolfram has <br> been found at several places forming nests in the granite but not <br> in association with cassiterite Touching the latter itself it is <br> mostly of a pitch-black colour occasionally translucent brown and <br> hyacinth-red and from some places greenish with a very pretty play <br> of rays of red and yellow colour through it Its crystalline form is <br> rather simple as regards pyramidal planes ; the prism is generally <br> however highly modified Twins like those from the Schlaggen- <br> wald mines are very abundant ; and crystals perfectly developed all <br> round both twins and simple ones the latter with twelve-sided prism <br> and one pyramid are not rare amongst the ore washed from the drift <br> As regards the drift it is very rich and consists of recent granite <br> detritus from 6 in to 2 ft thick spread all over the range and of an <br> older probably Pliocene Tertiary cemented gravel of several feet <br> thickness and mainly composed of waterworn pebbles and boulders <br> of quartz frequently rock-crystal and cairngorm hard granite and <br> hornstone capping the top of the range and dipping most likely <br> analogous to the older gold-drifts at other places beneath the basalt <br> adjoining see sketch section fig 1 <br> Fig 1 ” Sketch section across the becl of the Maeintyre River <br> Macinfcyve River <br> a Basalt 6 Older Drift c Granite 39050909 120601 51125 Page 7 Text v 29 http //www biodiversitylibrary org/page/39050909 1873 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 29 1873 Geology Periodicals Smithsonian Libraries bhl page 39050909 dc identifier http //biodiversitylibrary org/page/39050909 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-24 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13368815083 2015-08-26 10 53 12 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1873 Photos uploaded from Flickr by Fæ using a script | ||||
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