Coal Basin of New South Wales. i 
as Mr. Clarke. The circumstance of auriferous drifts not being 
found in miocene beds is a species of negative evidence that 
must undoubtedly yield before a solitary specimen positively 
instancing the direct converse. The actual existence of gold 
at the very earliest times would. appear to be clearly 
proven. Whether its formation was gradual, extending 
over a long period, and developed in different areas at 
different dates, is another question. A few isolated reefs 
may have been thrown up previous to the mesozoic ages, 
and the great majority of them may have had no existence 
until just previous to the advent of man himself. There is 
ohe circumstance in some way seeming to bear'upon Mr. 
Selwyn’s theory, which ought not to be passed over. At 
Keilor, Flemington, near Ivanhoe, and in many other por- 
tions of the colony, quantities of an immensely hard tertiary 
rock are met with. The formation is evidently the result of 
some large out-pouring of water, highly charged with sili- 
cious matter. Now grant, as many suppose, that quartz 
reefs are of aqueous origin, and the result would be that the 
springs forming them would escape from their respective 
fissures, still strongly charged with silica, which would be 
speedily deposited as a matter of course. Can it be that 
the beds referred to are traceable to such a source; if so, 
then the quartz is clearly of tertiary origin, since the silicious 
deposits of which I speak contain leaves and plants, which I 
believe are pronounced by the Government botanist, Dr. 
Mueller, to be of not earlier than the miocene period ? 
A careful study, however, of the carboniferous rocks of 
New South Wales will, I think, suggest a reason other than 
that of the modern origin of gold, why our miocene rocks 
are not auriferous. They, the carboniferous beds, have 
everywhere been subjected to immense denuding forces. 
They once extended over an area much greater than that 
which they at present occupy. The rocks of Western Port, 
of Cape Otway, of North Gipps Land, Arapiles, and Mans- 
field, are probably their equivalents, and very possibly their 
outliers. Victoria, in fact, as I am informed, is pretty 
thickly studded over with isolated patches, which seem to 
show that such rocks once covered by a thick layer the 
major part of the entire colony. The rough section before 
you shows Mr. Selwyn’s views relative to this matter, and 
by this it will be seen that a vast dome of sandstone, since 
_ Swept away, extended from North Gipps Land to the Gram- 
pians. Now, whilst this dome remained still intact no 
