Chap. XIX.] 
GOLD OF VICTOEIA. 
465 
quartz-reefs yet untouched should prove as rich as several which are now yield- 
ing fair profits to the miner, the future supply of gold from Victoria will be much 
more durable than that derived from any other known auriferous country, 
In fact Victoria is, as far as I know, the richest gold-country of which history 
records an example, whether we look to the very wide diffusion of the auriferous 
debris of different ages, which Mr. Selwyn estimates to be spread over 10,000 
square miles, or to the quartz-veins in the slaty Silurian rocks, which, by the 
improved processes of crushing, are forced to yield a supply which could not 
have been obtained by any of the old methods of extraction (see note, p. 451). 
Mr. Selwyn has satisfied himself that the gold-quartz-veins of Victoria are 
confined to rocks belonging to my original ' Lower Silurian ' division in ascend- 
ing from the Llandeilo formation to those strata, charged with Pentameri, now 
termed Llandovery rocks. " In every part of the colony," says he, " where such 
rocks appear on the surface, they are intersected almost invariably in a me- 
ridional direction by quartz-veins, from the thickness of a thread to the di- 
mensions of 10 or 15 feet, and in marvellous abundance. Not one per cent, of 
these ' quartz-reefs ' has as yet been touched by the miner ; and therefore the 
chief evidence we have at present of their containing gold is in the richly auri- 
ferous and widely spread Tertiary deposits [Drifts] which everywhere accompany 
them, and which have undoubtedly been derived from their preexisting upper 
surfaces." 
In his highly instructive notes on the Physical Geology and Mineralogy of 
Victoria, published in 1866, Mr. Selwyn definitely tells us that gold occurs 
mainly in the quartz -reefs of the Lower and Upper Silurian rocks, and in the 
detrital accumulations of the Upper Tertiary ' cement ' and Drift-deposits, which 
owe their origin to the abrasion and denudation of the former*. Gold, how- 
ever, is found occasionally (he states) in sandstone, slate, granite, and diorite. 
This author admits the axiom I had laid down in former editions of this work, 
that, " although exceptions are known, it is by most quartz-miners acknowledged, 
so to speak, as a rule, that the gold becomes finer and finer, and more intimately 
mixed with the quartz and pyrites, the deeper the reefs are worked." In other 
words, the larger lumps are always nearest to the surface of the veinstone. The 
alluvial or drifted gold is said to be generally of finer quality than the 1 reef gold,' 
though the derivation of the former can usually be distinctly traced to adjacent 
quartz-reefs. Mr. Selwyn propounded an ingenious theory to explain this su- 
periority in the quality of the nuggets in the alluvial gold. He suggested that 
" particles of .alluvial gold may gradually increase in size through the deposition 
of metallic gold (analogous to the electro-plating process) from the meteoric 
waters which circulate through the Drifts, and which must have been during the 
time of our extensive basaltic eruptions, of a thermal, and probably highly saline, 
character, favourable to their carrying gold in solution." This theory has to some 
extent been sustained by Mr. Daintree's discovery that wherever woody matter 
(and it is frequent) is in the Drift, the iron -pyrites in cavities of the wood is auri- 
ferous; whilst Mr. Wilkinson has shown by experiment that a nucleus of gold im- 
mersed in a weak solution of chloride of gold does receive notable accessions in size 
when any vegetable substance is introduced into the liquid j but as Mr. Selwyn 
candidly admits there are still many doubtful points respecting this phenomenon 
to be cleared up, I prefer to remain in my old belief, that the large nuggets found 
in the Drift are simply the reliquiae of the chief masses of gold which once occu- 
pied the uppermost parts of the reefs, and that, like the blocks of many an an- 
* Notes on the Physical Geography, Geologv, and Mineralogy of Victoria, 1866, p. 44. 
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