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of the accumulation of tailings. The possible advantages of an under-
current such as has been installed in the Lowhee flume are obvious, for a
current of water is forced up through the water in the flume and tends to
momentarily check the main current and cause settling of the fine material
through the grizzly. The steel plates at the upper end of the flume were
first placed with 3-inch spaces between them for rifiles, and with 4-inch
rise on the upstream side. They were later changed so as to be level and
to have 4-inch spaces between them. Mr. Muller stated that the latter
arrangement had proved more satisfactory, and that further experimenta-
tion was being carried on to determine the best possible methods of saving
the gold.

Jack of Clubs Creek

Jack of Clubs creek has its source near that of Williams creek in Bald
Mountain plateau and flows northeast into Jack of Clubs lake. It is some-
what larger and longer than Williams creek and because Williams creek
proved to be rich in gold it was held for many years that Jack of Clubs
creek must be rich also. However, it has produced only about $225,000
in gold, although considerable mining has been done on it, whereas Williams
creek, flowing north, has produced several millions. The creek, the lower
part of which is shown on Figure 17, flows in a broad, deeply drift-filled
valley in the part below the mouth of its main tributary Pinkerton creek.
A short distance above the junction the creek flows for 800 feet in a narrow
rock canyon. In this stretch and for 800 feet above the canyon the creek
has formed a new post-Glacial channel. The old channel opposite the
canyon in the lower part of Pinkerton creek is partly blocked by morainic
deposits and is deeply drift-filled. Bedrock outcrops in the bed of the
creek opposite the upper end of Tucker lake, and here, also, the deep
buried channel is on the southwest side of the valley. A remarkably well-
developed high channel drained by McLellan creek occurs on the northeast
side and extends through to the valley of Jack of Clubs creek above the
canyon. Its upper end is about 100 feet above the level of Jack of Clubs
creek. In the upper part of the creek, a short distance above the part
shown in Figure 17, there is a small rock canyon and a buried channel
alongside. The ground in the valley bottom above the canyon is com-
paratively shallow—about 45 feet at the old Valincourt shaft just above the
canyon—and no paying deposits of gold have been found in it. The
deposits in the deep part of the creek below the canyon are 60 to over 200
feet thick and consist mainly of glacial gravels, with some glacial silt and
clay and surface alluvium. Boulder clay occurs in places on the northeast
side of the creek, but appears to be absent on the southwest side, where
glacial gravels are abundant and largely conceal the bedrock. Deposition
of glacial gravels on the southwest side of the valley, and lack of deposition
of boulder clay, may have been due to the fact that during the closing
stages of glaciation the ice remained longer on the northeast side of the
valley and ice melting and stream action were pronounced on the southwest
side. There are somewhat similar occurrences on other creeks in the area.
The absence of boulder clay, except in a few places, and the porous char-
acter of the gravels, have caused difficulties in sinking shafts to mine the
deep ground. These difficulties were largely overcome by sinking shafts