One
of the most interesting of the many suggestions as to the cause of the
distribution of the gold in the Victorian gold-fields was made by Mr.
T. A. Rickard in a description of some mines in the Buckland Mining
Division. He stated that the gold in each case occurred as a shoot
along the line of intersection of the quartz vein and a particular band
of country rock. Mr. Bradford's mission at Harrietville was to obtain
sufficient information regarding the reefs of that locality to show the
reliance to be placed on this suggestion.
His
report does not fully support Mr. Bickard's hypothesis, while at the
same time it explains the facts on which that hypothesis was based.
According to Mr. Bradford's survey of the field, the gold occurs in the
quartz reefs where they are intersected by lines of drainage. The
position of these drainage lines is naturally determined by the
arrangement of bands of impermeable rock, such as slate. Hence the
observations by Mr. Rickard are confirmed in some places ; but this
distribution of the gold appears to be a coincidence, and is not
universal through the field. Mr. Bradford explains these facts on the
view that the distribution of gold is determined by the agents which
control the circulation of subterranean gold-bearing waters.
Reference
should be made to the previously published reports by Mr. Bradford,
especially to Bulletin No. 2, on the Pyrenees, for an account of the
general principles of gold deposition on which he lays stress.
The
sedimentary rocks of the Harrietville district have been called Lower
Silurian; but this name has been altered in the report to Ordovician,
in accordance with the nomenclature now adopted by the Geological
Survey.
J. W. G.
