468 
SILUKIA. 
[Chap. XIX. 
estimated approximately. It matters nothing to the statist whether the richest 
portions of these golden Drifts, or accumulations of broken materials, were for 
the most part aggregated by causes now no longer in action, which power- 
fully abraded the surface of the hills (as explained in the previous pages, and 
particularly in the diagram, p. 460), or whether the diurnal atmospheric action 
for thousands of years has also been an effective agent. Both causes have 
unquestionably contributed to spread out and render more accessible a ma- 
terial the search after which in the solid rock is attended with much more 
difficulty. 
In the meantime a basis of all such researches and inquiries into the pro- 
bable amount of the drift- gold must be provided by good geographical surveys 
of the auriferous countries of Australia, as completing the work commenced by 
the late Sir T. Mitchell and his associates. On that important groundwork, 
geologists may record all progressive observations respecting a region formerly 
almost exclusively pastoral, but which suddenly became a great and populous 
centre of commerce through the development of its prolific gold-fields. 
In this Chapter I have abstained from alluding to many tracts more or less 
auriferous, and some rich in produce, which come under the same laws of dis- 
tribution as those described in the text. Such, for example, are the phenomena 
of the southern provinces of the United States (South Carolina &c). 
In Canada it was proved, some years ago, that, besides the occurrence of 
native gold in the Drift-deposits, the metal also occurred in quartzose and 
metalliferous veins or lodes traversing Lower Silurian strata (the Quebec Group) 
as well as beds at St. Francis on the Chaudiere, supposed to be of Upper-Silu- 
rian age. 
The supposition put forward by the Geological Survey of Canada (Report, 
1863, p. 519), " that the "precious metal was originally deposited in the beds of 
various sedimentary rocks, such as slates, quartzites, and limestones, and that by 
a subsequent process it has been in some instances accumulated in the veins 
which intersect these rocks," does not appear to be sufficiently supported by the 
evidence produced ; for no attempt is made to prove that these strata ever con- 
tain gold, except at the points of intersection where these metallic veins traverse 
them, and these veins may fairly be supposed to bring in the gold in question. 
This would also appear to be the case in the very recent discoveries of gold in the 
Laurentian rocks in the county of Hastings, at the Richardson's mine, which, 
from the descriptions of Mr. Sterry Himt and Mr. Michel (and specially of the 
latter, who inspected the ground), appears to have been sunk upon a vein of 
decomposed pyrites containing fragments of an anthracitic mineral, also in a 
crumbling, decomposed state *, and containing particles of gold disseminated 
through its substance. The ochreous or earthy matter and oxide of iron are 
derived evidently from the decomposition of the pyrites, whilst the ferruginous 
bitterspar may be a secondary product of aqueous action on the neighbouring 
rock, which is stated to be chloritic. That the gold occurs in the lode itself, 
and not in the strata, is inferred from the analysis made by Mr. Michel, who 
states that he found no trace of gold in the rock, except in one case, in imme- 
diate contact with the auriferous lode. 
The discovery of gold on the Frazer River, in British Columbia, was quite to 
have been expected, as the ridges between which that river and its affluents 
flow are simply prolongations of the auriferous chains of California, which are 
* Anthracite is frequently found in fragments dal such nodules are generally in a decomposed 
or nodules in the granite and metalliferous veins state, so as to crumble into powder upon the least 
of Norway and Sweden. In the granites of Aren- pressure of the fingers. 
