74 FAIRBANKS AND RAMPART QUADRANGLES. 
Mining. — During the summer of 1904 work was being done on Dis- 
covery claim, about \\ miles above the mouth of the creek; and on 
No. 17, a claim about 4 miles above the mouth. Several claims be- 
tween these were being prospected. 
On Discovery claim a flume 2,000 feet long, 30 inches wide, and 20 
inches deep carried water to a bench about 16 feet above the creek. 
The bench was covered by 5 to 6 feet of gravel and over this was 1 to 
4 feet of muck. The muck and gravel were practically all sluiced 
off, and the loose bed rock, in which the gold is found to a depth of 
about 18 inches, was shoveled into sluice boxes. The bed rock is 
partly a diabase and partly a much-folded brown, cherty shale stand- 
ing on edge. The large bowlders were moved by hand. Three men 
ground -sluiced an area 75 by 150 feet in thirty days. The gold is 
mostly bright, smooth " pumpkin seed," with a few small rough 
pieces (PI. III). A considerable amount of small barite pebbles and 
some hematite occur in the concentrates. 
On claim No. 17-A a hydraulic plant was installed during the sea- 
son of 1904. About a mile of combined ditch and flume had been 
put in, about 3,000 feet of which was flume, 32 by 18 inches, deliver- 
ing 300 inches of water under a head of about 75 feet. A No. 1 
Hendy Giant with a 3-inch nozzle was being used. 
In working the ground the niggerheads and moss are torn up with 
a team and harrow and washed off with the nozzle. The ground is 
then left for a week, during which time the muck will thaw 1 to 2 
feet. This is then washed off. The process is repeated until the top 
is removed. The remaining gravel thaws much more rapidly 
than the muck. It is found that the gravel can thus be thawed and 
made ready for sluicing much faster than a hydraulic giant working 
steadily can wash the gravel into the sluice boxes. In one instance 
an area of 125 by 250 feet was w T orked out in 40 days. The gravels 
are 2 to 12 feet thick, averaging about 6 feet, and are covered by 1 to 
40 feet of muck. The maximum thickness was found at the mouth 
of a small tributary gulch where the gravel is mixed with angular 
fragments of rock. The muck contains much ground ice, which 
thaws readily when hydraulicked. The ice occurs occasionally as 
" dikes." One such was encountered over 400 feet long and 2 feet 
thick, intersecting the surface layer of muck and a flat lenticular mass 
of ground ice down to the gravel, making a depth of 12 to 15 feet. 
The gold is found through the lower 3 feet of gravel and in the 
rough broken bed rock, which is made up of diabase and thin-bedded 
quartzite. It is bright and smooth, and nuggets up to 10 ounces in 
weight have been found. There is a small amount of rougher gold. 
Colors of gold are said to occur throughout the length of the creek, 
but no workable deposits have been found above the eastern limit 
of old gravels on the high bench already described. The larger part 
