bed-rock,
twenty-five feet deep, was bottomed. The hole was filled with gravel,
but no pay was obtained. The pay stratum was found to be on a level
with, and a continuation of, the pay stratum of the rest of the claim.
On the other hand, at the Chesnau and French Hill claims whenever
these hollows are found a large yield of gold is invariably obtained.
The
experience of miners in the gold-fields of Victoria has led to the
conclusion that " in large auriferous rivers' gold is always found on
the bars or points, and not in the deep pools or bends." In
substantiation of this are cited Reid's Creek, Woolshed, Twist's Fall,
Yackandanah near Osborne's Flat, and Rowdy Flat; at each of these
places large holes were cleaned out and only a few colors obtained,
while shallow flats immediately below them were very rich.*
In
gulch-mining it sometimes happens that from the position of the
bed-rock the detrital accumulations assume the form of reclining cones,
the apex reposing upon the top of the hill. Where such is the case the
bulk of the gold is concentrated in the lower end of the deposit. These
gulches are frequently found to be exceedingly rich.
These
facts are cited merely as an explanatory outline of the subject, and to
show why a system of sluicing should be adopted which bottoms the
entire deposit.
EXAMPLES OF THE COMPARATIVE VALUES OF THE DIFFERENT GRAVEL STRATA.
North Bloomfield.—To
ascertain the comparative value of the gravel strata at Malakoff,
Nevada County, on the ground of the North Bloomfield Mining Company, a
series of tests was made of the dirt extracted from a shaft sunk, two
hundred and seven feet deep, in the channel. The first one hundred and
twenty feet from the surface
* " Gold-Fields and Mineral Districts of Victoria," p. 134.
