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by valley glaciers. No strie are known to occur in the bottoms of the
deep, narrow parts of the valleys, except in the upper part of Cunningham
creek, where, however, the valley bottom is comparatively wide. Moraines
formed by valley glaciers occur in Lightning Creek valley below Stanley;
in Slough Creek valley opposite and below the mouth of Devils Lake
creek; below the mouth of Jack of Clubs creek; and at other places in the
valley bottoms. These moraines, forming as they do part of the surface
deposits in the valley bottoms, must have been formed during the closing
Stage of glaciation. The evidence of valley glaciation is, therefore, much
more pronounced than that of an extensive ice-sheet. Nevertheless, the
presence of erratics and boulder clay at high altitudes, the foreign deriv-
ation of some of the drift in the several valleys, and the occurrence of
boulder clay at altitudes too great to be referable to valley glaciers, all
go to show that an ice-sheet of considerable thickness did exist. The
general direction of movement of this sheet, as indicated by the direction of
transport of the erratics, was towards the southwest. The small amount
of drift on the uplands, however, shows that the movement was very
slight and effected very little transportation of glacial drift, and it seems
probable that the upper surface of the ice-sheet coincided very nearly with
the surface of the uplands at an elevation of 6,000 to 6,200 feet. The
small amount of movement was due to the fact that the ice-sheet through-
out central British Columbia, during the time of its maximum develop-
ment, was practically hemmed in by mountain ranges. It had, therefore,
little movement as a whole, but was drained by large glacial tongues extend-
ing through the passes.

The average thickness of glacial drift over Barkerville area probably
does not exceed 100 feet and was mostly derived from the higher levels.
The narrow, V-shaped valleys were eroded only slightly by the ice and
there are many places in the area—for example, at the old China hydraulic
pit on Wolfe creek, in the bottom of the Lowhee pit near its head, and at
the old bedrock tunnel on the northwest side of Burns mountain—where
the bedrock is deeply weathered to a residual clay and is overlain by un-
weathered glacial drift. The lack of ice erosion in the deep and narrow
valleys explains why gold-bearing preglacial gravels were preserved in
places, and were buried beneath glacial drift, which, although abundant,
was derived mostly from the upper parts of the valleys and uplands where
no preglacial placers now exist.

The glacial drift consists in part of boulder clay and moraine material;
in part of stratified, fine sand and silt—the “slum” of the placer miner;
and in part of stratified gravels and bouldery deposits. The boulder clay,
which is usually referred to by the miners as “clay,” in places contains
comparatively few boulders and in other places is very stony. The upper
weathered part is a yellowish, unstratified clay; the part below water-
level is in most places bluish grey. The part above the permanent ground
water-level is in many cases hardened or slightly cemented as a result of
alternate wetting and drying and is, therefore, difficult to hydraulic. The
upper more clayey part of the boulder clay, probably, was formed from
materials included in the ice and deposited after its melting; the lower
stony clay was formed beneath the ice.