f* ' ndle. J BIKCH CE EE K REGIO N . 61 
lumpy in character. The present annual production is probably 
under $50,000 ; the total production has been about $1,500,000. 
Ground is now worked from the headwaters throughout the narrow 
part of the valley, a distance of about L2 miles, but i( was not until 
1900 that the lower part was found to be productive. The open-cut 
system has been employed on most of the ground. It has been found 
advantageous to work the cuts generally to a width of L6 feet. The 
depth is such that dirt can be shoveled directly into the sluice boxes 
Little drifting has been done thus far on the creek, but it was pur- 
posed during the winter of 1904 to work ground on the bench by 
this method. About 35 men were on the creek at the end of August, 
1903. The bench trail from Central House across the flat, about 4 
miles, to the entrance of the valley is a good one, but in wet weather 
that along the creek is soft and difficult to travel. 
Mammoth Creek. — Mammoth Creek, which unites with Porcupine 
to form Crooked Creek, is itself formed by Mastodon and Independ- 
ence creeks, which unite about 4 miles to the southwest. Miller 
Creek joins it from the west about 2 miles above its union with Por- 
cupine Creek. About a mile below this last junction it flows through 
a flat 200 to 300 feet wide, gradually widening as the Porcupine is 
neared. On the east side spurs descend abruptly from an altitude 
1,200 feet above the creek. On the west the valley is bounded by the 
termination of a narrow spur between Mastodon and Miller creeks. 
and that of a broad, low spur between Mammoth and Porcupine 
creeks. 
The bed rock is quartzite-schist and granite, and the gravels. a re 
made up mostly of these rocks, with a small proportion of vein quail/. 
The average depth to bed rock is about 10 feet, and the upper 2 or 3 
feet are waste. The gold is rather fine, but the ground is probably 
rich enough to be worked at a profit on a large scale. One of the 
interesting developments has been the introduction of machinery. A 
steam shovel, shown in PL XIV, /l, was shipped in over the snow from 
Circle during the winter of 1903 and gotten into position to work the 
ground during the following summer. This shovel is capable of 
handling 500 cubic yards of dirt in ten hours, and has a working 
width of 26 feet. Twelve hundred feet of track have been provided 
for it, and there is a face of gravel of about 10 feet upon which to 
work. The shovel holds about three-fourths of a cubic yard, and the 
dirt is dumped from it into a car of \\ cubic yards capacity, which is 
drawn by cable up a steep grade, a vertical distance of 22 feet, to the 
boxes. The flume, which has a capacity of 5 sluice heads, brings 
water from a point 1,700 feet upstream. It is said 3 sluice heads are 
sufficient for all the gravel the shovel can furnish. The system 
requires \\ cords of wood a day and the attention of about L5 men on 
a shift. A bed-rock drain 400 feet long carries away the water from 
