AIaitlaxd. — Western Australian Geology. 
217 
iiioi)ate of antimony, Btibiotajitalite, tho tivst discovery of tantalum 
ore in Australia, was made in Greenbuslies in 1893 and has so 
far l)een found only in California. 
T(> these may be added the group of telluride minerals which 
occur ill but few localities throughout the world and which have 
been so extensively mined at Kalgoorlie and Boulder, the chief 
gold-jiruducing eentie of the State. 
The tellurium-carrying minerals constitute one of the most 
distinguishing characteristics of the ores of Boulder and Kalgoorlie, 
being the main source of over 16 million ounces of gold from 
this mining centre. 
With such an embarras des riehesses in the broad domain of 
mineralogy it is not at all surprising that Western Australia’s 
eontributious to what may be termed mineralogenesis have been 
so extensive and of such a- high order. 
The igneous roeks occurring in and associated with Pre-Cambrian 
formntions iiave also thrown a great deal of light upon many of 
the more iinj'ortant jiroiilems of petrogenesis. 
An outstanding feature in connection with the investigations 
is the important juirt which the upwelling of the molten granite 
and its comjilementary dykes, with the concomitant sagging of the 
overlyiiig rocks into intervening troughs, has been found to play 
with regard to the gold-bearing’ and other mineral deposits. 
A iH'sult of this granitic invasion has been the formation of 
fracturt' ])lam's and other lines of weakness, having a general north- 
westerly alignment, along which the mineral-bearing solutions in 
circulation have found an easy passage, Avith the introduction of 
the metalliferous minerals; this being the latest expression of the 
subterranean forces in operation. 
It is therefore the rocks along ami adjacent to the margins 
of the granites which have proved to be the liosts for ore and 
Avhich constitute the chi(T hope for an expanding mineral industry. 
The existing laud surface bears no relation whatsoever to that 
which existed wlieii the ore bodies were formed. The limits of 
ore deposition, i.e., cooling and consolidation, are not confined to 
a few hnudred feet from the surface, but are to be measured in 
miles rather than in fathoms. The inferior limits of mining, Avhen 
viewed from the broad standpoint, are determined rather by the 
cost of production than by the exhaustion of ore. 
Ore formation i>rocesses are at present in active operation at 
enormous depths beneath our feet, for such appear to be due tg 
