pkindle.] FORTYMILE REGION. 49 
present conditions the occurrence is of interest chiefly in pointing to 
one possible source of the placer gold occurring on Chicken Creek. 
This rock is the bed rock on the bench between the Chicken and the 
Lost Chicken. A porphyry of about the same composition but very 
different in appearance outcrops abundantly on the south side of the 
divide between Chicken and Franklin creeks. 
On the broad spur east of Stonehouse Creek, about 1 mile north of 
the junction of the Stonehouse and the Chicken and about 500 feet 
vertically above it, gold has been found in place in dark shales lying 
on the nearly flat surface of the fine-grained, dark-colored porphyry 
to which reference has just been made. At this locality a 10-foot 
hole has been sunk and a crosscut of less depth run to a distance of 
35 feet on the w T est side. In the bottom of the hole there is exposed 
about 2 feet of the porphyritic rock, containing abundant corroded 
quartz phenocrysts up to 3 mm. in diameter, and some larger ones of 
plagioclase feldspar in a fine-grained, dark-gray groundmass contain- 
ing some pyrite. This hard, tough rock is considerably jointed and 
much discolored by iron rust along the joint planes. On top of it is a 
10-inch layer of soft black material of the consistency of clay, suc- 
ceeded by 5 to 6 feet of blackish shales, much jointed and having a 
general dip of 25° to the southwest, thus conforming with the surface 
of the porphyry and that of the black layer. These shales contain 
many calcite and some quartz seams-, but these are rarely more than 2 
inches in thickness and do not extend into the black layer below them. 
The quartz seams were found to contain considerable pyrite, and the 
thinner calcite seams contain interesting specimens of gold, which 
occurs in thin plates along planes in the calcite. The shales are cov- 
ered with 2 to 3 feet of soil. 
Twelve hundred feet southwest of this locality a similar porphy- 
ritic rock occurs, but here the rock is more coarsely crystalline and 
more like a dark-colored granite in appearance. It was covered with 
a thin deposit of gravel resembling the bench gravels found at other 
ocalities within the valley of Chicken Creek. The igneous rock 
probably forms the main mass of this broad spur and is overlain 
locally by the shales. The distribution of the shales and other pos- 
sible occurrences of gold with them have not been determined. Shales 
somewhat similar in character are cut by the ditch on the east just 
above Stonehouse Creek, where they are covered by about 5 feet of 
muck. 
The locality above described has produced many beautiful speci- 
mens of gold associated with calcite, and is of present interest chiefly 
n pointing out another possible source of the placer gold. No work 
las been done to show whether the shales have been uniformly 
nineralized over considerable areas. If such were the case and con- 
Bull. 251—05 m 4 
