rock crops out on all sides, or in such a
manner as to indicate the existence of an
ancient valley at a higher level than the
present drainage system of the country, it
may then be taken as a guide in pros-
pecting.

The period of the greatest depression
of the land, which corresponds with the close
of what I term the older tertiary epoch,
was marked in some districts of the Pro-
vince by volcanic eruptions, during which
basaltic lavas was poured forth from rents
in the earth's crust, and flowed over what
were then the lowest levels of the sea bot-
tom, but which have now, owing to the
preserving influence of the hard, tough,
basalt, become elevated to lofty positions.
Like the "White made hills," these basalt-
capped hills often cover deposits of rich
auriferous drift. There is evidence of vol-
canic ejections during this period in
the lower part of the Manuherikia Valley, but
none of the characteristic flat-topped hills
were observed. These are, however, very
prevalent in the district from the gorge of
the Taieri, at the head of Shag Valley,
southward towards Dunedin. Highlay
and Flat-top Hills form very perfect ex-
amples.

It was with the first display of volcanic
activity that the elevation of the land
commenced, and although, as is always the
case, this elevatory movement was accom-
pained by degradation of pre-existing
strata, rather than by the formation of new
deposits; yet under favorable circumstances
this very degradation gives rise to local
deposits, which are those I shall pro-
visionally term, the newer tertiaries.

During this period, the rock-bound basin
afterwards to be drained by the Taieri and
Molyneux rivers, became converted into a
system of lakes, connected by streams,
which slowly excavated terraces, and de-
posited in a more perfectly assorted form
the materials which composed the plateau.
In the lakes, the sorting process would be
still more perfectly accomplished, the
coarser materials being deposited at the
inlet, while the finer sediment would only
settle in deeper water, or towards the out-
let. The Taieri Lake is the last remnant
of this once great expanse of fresh water,
but the materials which were deposited in
this manner still exist, forming terraces
and cliffs of shingle, gravel, clay, and fine
loam. As the main exit channels of the
basin were deepened, the lakes were in
time drained, and their materials again
assorted by the corrasion of the streams.

This sorting process, which may justly
be compared to the action of a sluice in
ordinary gold washing, has been contin-
uously in operation during the lapse of vast
ages, sifting and separating, according to
the specific gravity of its component parts,
the debris of the schistose rocks, and pre-
pared the way for the gold miner by con-
centrating the precious metal in a smaller
and smaller quantity of wash-gravel. Gold
being the heaviest material contained in
these deposits, must be looked for as a re-
siduum, remaining behind after the lighter
parts of the schistose debris has been
removed by the action of water. When,
therefore, it is found on the bars or in old
channels of a stream, we must look to the
debris, or drifts, in the neighbourhood,
as its immediate source, and the more they
bear signs of having been well sorted,
the probability is increased of finding the
heavier materials, and among these, the
gold, gathered into leads towards their
base.

From these considerations it will be per-
ceived, that by simple natural operations
similar to those now in progress, we may
have a great variety in the mode of occur-
rence of the gold in these so-called "alluvial
drifts." I do not underrate the agency of
streams in wearing and cutting the solid
rock, and also carrying forward to a lower
level immense quantities of detrital matter.
But every practical miner knows how in-
adequate any theory of river action would
be to account for the "gold drifts" in all
situations where they are found. We must
rather, as I have endeavoured to show, look
for their origin in a sequence of grand
changes in the natural features of the
country, dependent upon slow alterations
in the relative distribution of sea and land
in the first instance, followed by the for-
mation of great inland lakes which were
gradually dried up as the existing drainage
systems became established. Exactly
similar deposits occur in basins upon the
western slope of the Rocky Mountains of
North America, from an elevation of 5000
feet almost to the sea level, and extending
from California northwards into British
Columbia. The absence of basalt-topped
hills, and the large scale on which the
terraces have been developed, give the
Manuherikia and Taieri Plains a striking
resemblance to the upper valleys of British
Columbia. Before arguing from this su-
perficial resemblance, however, any simi-
larty in the richness of their auriferous
deposits, it is important to compare the
nature of the schistose rocks from which
the gold has been derived.

The prevailing rock which forms the
framework of the Province embraces many
varieties of gneiss and mica schist, but
generally imperfectly formed, in so far that
the evidence of mechanical origin has rarely
been obliterated from the intimate particles,
while in all cases the original lines of
bedding remain distinct, and mark changes
in mineral character. As compared with
the Lower Silurian auriferous rocks of
Victoria, although they are more altered
in mineral structure, yet they have been