ECONOMIC GEOLOGY. 41 
Fox Gulch is a small northerly tributary of Goldstream Creek. 
Little mining has been done on the lower part of the creek where 
the alluvium is probably 30 to 40 feet deep. Several claims have been 
worked about 3 or 4 miles from the mouth, at a point where the 
gravels are 8 to 10 feet deep, overlain by muck about 10 feet thick. 
The pay streak here is rather narrow and the reported values are not 
high. 
Some gold has been found on Big Eldorado and O'Connor creeks 
but as neither has been visited by a geologist details regarding them 
are lacking. Both these creeks are tributary to Goldstream from the 
north, and each is about 5 miles in length. The pay streak on Big 
Eldorado Creek is said to be narrow, but some mining has been done. 
Work on O'Connor Creek is said not to have gone beyond the pros- 
pecting stage (1907). Ground is reported to be from 100 to 130 feet 
deep. 
Engineer Creek, about 5 miles in length, a southerly tributary of 
Goldstream, has also become a producing creek during the last two 
years. The placers of this stream have not -been studied by any 
geologist. 
The gravels on some other small tributaries of Goldstream Creek 
have been found to be auriferous, but no values have been discovered. 
This does not signify, however, that they are not worthy of careful 
prospecting. 
CLEARY CREEK. 
Geary Creek has been the best producer of the region. Workable 
deposits have been found along about 7 miles of the stream and far 
out into the Chatanika flats. The limit of their extension into the 
flats has not been determined. Chatham Creek, only about a mile 
long, has been a good producer. Considerable work was done on 
Wolf Creek in 1903, but since that time little gold has been found 
there. 
The deposits of the main valley range in thickness from a few feet 
to more than 120 feet, averaging about 60 feet. The pay streak has 
a maximum thickness of about 14 feet and an average for the creek 
of about 5 feet. The width of the pay streak, under present mining 
costs, ranges from 30 feet or less to several hundred feet. The aver- 
age value in the pay streak for much of the valley appears to be about 
$10 to the cubic yard. The pay streak is rather uniformly developed, 
but the valley is so wide that its location requires much prospecting. 
The position of the pay streak in the valley is at variance with the 
course of the present stream. The creek makes one large bend in 
its course, above which the pay streak is altogether on the wesl side, 
several hundred feet from the creek, except at the head. It cro 
the valley at the bend, and throughout the lower pari is found on (lie 
