Suggestions for further Development of Gold Mining. 133 
consists of exposed Silurian rocks, the belts can easily be followed, 
and the quartz reefs or alluvial deposits tested at or near the 
surface ; but when we consider the comparatively small width, 
north and south, of the exposed Silurian rocks composing the 
western portion of the main mountain system, in which our richest 
gold-fields are situated, and the maintenance of their character from 
place to place by the auriferous belts within that width, wo are 
led to the conclusion that by following the lines of extension of 
those belts, and penetrating the newer formations overlying the 
Silurian rocks northward or southward of the Main Divide, we are 
likely to discover fresh groups of auriferous quartz reefs tra- 
versing the concealed bed-rock and auriferous gravels overlying 
it in their vicinity. This remark applies not only to Victoria but 
to the entire breadth of Australia, from Victoria to the Gulf of 
Carpentaria, for there is no reason to doubt the continuance of the 
Victorian group of auriferous belts beneath the newer formations 
of the western portions of New South Wales and Queensland. 
There is eveu a fair probability of discovering payable alluvial 
gold in the lowest beds of Marine Tertiary, Mesozoic, or Upper 
Palaiozoic formations whore these consist of gravels or conglom- 
erates, and rest immediately on Silurian rocks on or near the lines 
of extension of any of the known auriferous belts. In fact, con- 
sidering that in such localities the Silurian rocks have very likely 
been subjected to greater degradation than in the mountain 
districts, and bearing in mind the tendency of gold to remain nearly 
stationary during the removal of large quantities of other materials, 
it is not unreasonable to infer that gold may thus be found in large 
quantity, though probably more widely and irregularly distributed 
than it would be in narrow leads of fluviatile origin. 
No doubt the difficulties to be encountered would be great, and 
search in such directions would not be justified except on excellent 
data obtained where the Silurian rocks were near the surface; but 
nevertheless, there are reasonable grounds for hope that, with 
increased knowledge and improved mining appliances, the auri- 
ferous belts will, at some future date, bo traced for a far greater 
length than they may be at present supposed to extend to. 
It would be impossible to say how deep it would be necessary 
to sink before reaching the bed-rock in the Murray Valley for 
instance, but I believe that in any portion of it lying to the east- 
ward of the meridian of Stawell, the greatest depth would not 
exceed 1,000 feet. In the meantime, however, there is abundant 
scope for exploration in search of gold, whether quartz or alluvial, 
in localities where the depth would be comparatively trifling, and 
where the proximity of proved auriferous country -would warrant 
the expenditure necessary to prosecute the search. I will there- 
fore now proceed to briefly describe the principal known auriferous 
belts from the western to the eastern portions of the colony, and 
