48 FORTYMILE, BIRCH CREEK, AND FAIRBANKS PLACERS, [bull. 251. 
values vary from $50 to $175 to the box length, and a considerable! 
portion of the ground probably averages about $1 to the square foot. 
The gold is different from that of the other creeks. It is usually 
rather fine, much of it is granular, and the color is generally dark. 
Some of the gold is rather rough and is frequently found with quartz 
attached. No large nuggets have been found. 
The bench between Chicken and Lost Chicken creeks is about 275 
feet above the valley. Ground was located at the head of the Lost 
Chicken in 1901. Several holes were sunk along the creek and op the 
bench, and in the last one pay was found at a depth of 33 feet. One 
hole sunk in the west side of the bench near the top is interesting in 
that sandstone with plant-bearing shales was found at a depth of 90 
feet, overlain by loosely cemented gravels surmounted by 15 feet of 
muck. In the fall of 1902 some drifting was done on a portion of the 
ground, which averaged about $1 to the square foot. Near at hand 
two shafts were sunk to bed rock, one 53 feet and the other 45 feet in 
depth, and a dump obtained, which was estimated to contain from 
$35,000 to $40,000. This is shown in the accompanying photograph, 
taken after $25,000 had already been washed from it (PL IX, B). 
The bed rock is of the same dioritic type as that already referred to 
on Mosquito Fork. The 45-foot hole was sunk to bed rock through 
23 feet of muck and 22 feet of gravel and the upper portion of the 
decomposed bed rock was taken out along with' the gravels. These 
are the same in kind as the recent stream gravels, but are somewhat 
finer and show more wear. The discovery of gold on this bench has 
led to much activity in prospecting the benches throughout the region, 
and considerable work was under way west of Chicken Creek on the 
high benches of Mosquito Fork. 
Chicken Creek has a further interest in that two localities have 
been found bearing on the origin of the gold. One of these is about 
2 \ miles west of Chicken Creek on Mosquito Fork. At this point 
on the north of Mosquito Fork there is a steep canyon wall composed 
of a medium-grained greenish rock having about the composition of 
a quartz-diorite. On the side of this canyon wall, about 200 feet 
above the stream, occurs a mineralized zone, which has a thickness on 
about 6 feet and a strike of about N. 25° W., in which weathering 
has produced brilliant red and yellow colors. The rock within this 
zone is mostly decomposed to a kaolin-like mass, containing abun- 
dant fragments of quartz seams. This material pans fine flour gold. 
Assays of two specimens for the Survey by E. E. Burlingame & Co., 
Denver, gave for the one, in ounces per ton, gold 0.58 and silver 0.10; 
tor the other, gold 0.3G, silver 0.10; or an average of the two of about 
$9.70 in gold per ton. No drifting has been done and the specimens 
were taken directly from the surface. The extent of the deposit was 1 
still unknown, and as such values would not pay for working under 
