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yielded it in abundance, even though the gold was not visible 

 to the naked eye. But whenever these rocks are found in 

 conjunction with Silurian slates, gold deposits may be con- 

 fidently looked for, especially if quartz veins are found also in 

 connection therewith. 



It is by the disintegration and denudation of these rocks 

 that alluvial drift becomes loaded with gold, which is washed 

 down into the valleys and gullies below. And where the 

 dykes of diorite or granite forms the bed rock of the " lead," 

 the gold is generally in greatest abundance — it being re- 

 tained or arrested in the joints and crevices of the denuded 

 rock. On each side the drift or " wash " contains only the 

 finer or less weighty particles. 



The discovery of rich auriferous reefs is, in many instances, 

 brought about by the removal of the overlying " wash " or 

 drift ; and some of the most flourishing reefing districts of 

 the present time in Australia were originally only worked for 

 the alluvial gold. When a reef is laid bare by the miner 

 under these circumstances, there is by far greater likelihood 

 for it to be payably auriferous than otherwise, and the rich- 

 ness of the overlying drift is in a measure a test of that of 

 the vein of quartz thus exposed. So every alluvial miner is 

 strongly advised to search diligently for hidden quartz veins 

 in the bed-rock of his claim. The same, in fact, may be said 

 of all mineral veins. The drift containing the mineral can 

 only have been derived from some neighbouring vein, which 

 probably, by " stripping," would be discovered if persevering 

 attempts were made to search for it. Alluvial mining, 

 then, leads to quartz-mining, and in the most success- 

 ful instances is the only prelude to it. I recommend this fact 

 to be noted by the capitalists of Tasmania, when 

 contemplating investment in gold-mining ; for I am 

 afraid vast sums are spent in quartz reefs that can 

 never be otherwise than unj^roductive. The most 

 permanently payable auriferous reefs seldom contain 

 gold alone, but are usually intermingled with iron and 

 cof)per pyrites and other sulphides. Grold, too, is rarely found 

 in a pure state, but almost invariably alloyed with a varying 

 percentage of silver. Pyritous quartz is a good indication 

 of the presence of gold ; but in this case the precious metal 

 is so tightly bound up in the sulphides as to be only with 

 difficulty extracted therefrom. And it is a singular fact, 

 that, frequently when gold is proved by chemical analysis 

 to be present in this kind of stone in tolerably large pro- 

 portion, none is visible on the surface to the naked eye. It 

 is so finely divided, and so closely " held in bondage " by 

 the pyrites, as to be rendered invisible. When this pyritous 

 mineral is decomposed by a process of oxidation, the gold 



