The Formation of Gold Nuggets. ie 
strata have been denuded from above the silurian rocks. In 
the Blue Mountains, too, so far as I could gather, no evi- 
dence of tertiary deposits are anywhere apparent. Here is 
another proof of immense antiquity. It gives us time 
wherein to do our work, but, furthermore, it presupposes the 
existence of a force whereby the work would be carried on. 
If the district remained dry ground during the tertiary age 
it could only have done so as one or more of a group of 
islands. Under such circumstances the rainfall must have 
been vastly greater than at present. Torrents might have 
roared down these now dry hill slopes and even rivers have 
flowed along these now arid valleys. 
As to time for working out such grand results by such 
trifling agencies, of geologic time we know comparatively 
nothing. - We have long since abandoned the old interpreta- 
tion of Genesis, limiting the world’s age to 6,000 years. 
Having done so, ] am at a loss to know what reasonable 
argument can be adduced for refusing the geologist any ex- 
tension of time whatever, short of an eternity, during which 
the grand results he contemplates may have been brought 
about. 
Art. IL—On the Theory of the Formation of Gold Nuggets 
im Drift. By Mr. C. WILKINSON. 
(Read 11th September, 1866.) 
Mr. President and Gentlemen of the Royal Society,—It 
has hitherto been a moot question, and one which has 
elicited no small degree of discussion, respecting the occur- 
rence of larger nuggets of gold inthe drifts than have yet 
been discovered in any quartz reef; and that alluvial gold 
is generally of a higher standard than that Begg eC from 
the reefs. 
Many theories have been introduced to account for these 
phenomena: among them is one which does not appear“ to 
have received that amount of attention it evidently merits. 
J allude to that advanced by Mr. Selwyn, the Government 
geologist, suggesting the probability of gold existing in 
solution in the mineral water permeating the silurian rocks 
and the gold drifts; and that this water, in its passage 
through the drifts, became by some unknown means decom- 
