26 THE PORCUPINE PLACER DISTRICT, ALASKA. [bull. 236. 
down the bench deposit within a radius of 200 feet. A ditch leads 
the water from the upper part of Cahoon Creek to a penstock 400 
feet above the workings, from which a pipe line supplies the giant 
and furnishes power for an overhead trolley, which carries the large 
bowlders to a dump at the lower end of the claim (PI. X, B). 
Other claims. — Higher up on the south slope of the McKinlejj 
other bench deposits have been investigated, but nothing of impor- 
tance has been reported. The creek deposits above Woodin claim have 
not been developed sufficiently to prove their value, though some 
unsuccessful attempts were made to work claims on Cahoon Creek 
(PI. X, A). It is claimed by some of the prospectors that there is no 
pay on the Porcupine above the forks, nor beyond the mouth of Cahoon 
Creek on the McKinley. 
NUGGET CREEK PLACERS. 
Nugget Creek camp may be reached either by going up Salmon River 
some 20 miles, or by way of Porcupine, over the divide at the head 
of McKinley Creek. This creek rises in the same ice field which 
feeds McKinley Creek, and flows through a narrow canyon-like valley 
for a distance of 2^ miles into Salmon River. Like nearly all the 
tributaries of Salmon River, few of which are more than 2 or 3 miles 
in length, it enters from the north. 
Creek gravels. — The gravels of the present creek bed and the low 
side benches form the principal deposits in Nugget Creek. The 
former occur as rich pockets, filling the small glacier-scooped basins, 
commonly called potholes. The low bench deposits are usually very 
narrow and show more or less well-defined beds, a section through 
which would be as follows: On bed rock a 2-foot layer of glacial mud; 
above this a foot or more of cemented slate wash; then a 10-foot bed 
of pay dirt, consisting of large and small gravel wash; and capping 
this a few feet of rock slide and surface dirt. Many large angular 
blocks of diorite, several feet in diameter, occur in these creek gravels, 
adding greatly to the cost of mining. 
Seven claims have been staked on these creek deposits, two below 
and four above Discovery; the latter, however, is the only one which 
has been developed. To work the gravels on this claim the stream 
has been diverted into a flume, freeing the creek bottom and furnish- 
ing power for a derrick of considerable capacity, which handles the 
large diorite bowlders. A pipe line, fed from an upper flume, supplies 
water under a 200-foot head to the hydraulic plant by which the gravel 
banks are worked down through long sluice boxes 2 feet wide resting 
on bed rock. During the two years of development encouraging 
results are reported, and it is believed that future exploitation will 
yield large returns. 
