36 ALASKAN MINERAL RESOURCES IN 1905. 
PETERSON CREEK. 
The Peterson group of claims is situated on the northeast side of Peterson Creek, 4 miles 
by wagon road from Pearl Harbor. Although prospecting lias been done on all the claims, 
the Prairie claim has been developed most extensively. The ore body is a wide, flat-lying 
mass of quartz, striking X. 30° W., and inclosed in black slate, with arsenical pyriteas its only 
sulphide. Several shafts have been started at various points, both on and away from the 
deposit, but no systematic work has been done. 
WINDFALL CREEK. 
Starting from a point on Windfall Creek one-half mile above Windfall Lake, the placer 
claims of the Detroit Alaska Mining Company extend to the headwaters of the creek. The 
usual route to the mine workings, which are on claim No. 1 . is by wagon road and trail from 
Eagle ( o\ e. a distance of 7 miles. The gravel deposit under attack is 150 feet in width, 20 
feet in dept h, ami extends for a claim's length above the present workings to a point where it 
is eut oil by a canyon. About 10 per cent of the gravels consist of cobbles and bowlders of 
granite, greenstone, and quartz, which average from 1 to 8 inches in diameter. No clay 
st rata were observed, t hough a narrow bed of -.and. which is said to be the richest portion of 
the deposit . occurs 2\ feet above bed rock. The gold itself is hackly and of a dull color and 
is usually found in a line state. The bed rock consists of bands of slate and greenstone, the 
trend of which is followed by the creek. A new hydraulic elevator was installed in 1904 and 
the water-supply flumes enlarged. This season was exceptionally dry, and actual mining of 
the gravels could proceed only at intervals. The results obtained, however, when operating 
were said to be satisfactory. It is planned in L906 to build a ditch and divert Hie upper 
waters of Montana Creek into Windfall Creek, and thus materially increase its present 
volume of water. 
The Smith & lleid group of claims lias been located since 1893 at the head of Windfall 
Creek and small developments made each succeeding year. In 1S97 and 1898 a tunnel 
125 feet in length was driven to undercut an ore body exposed on the surface, but the results 
were not satisfactory. Since then assessment work only has been done. The lodes exposed 
are both quartz and mineralized chlorite schists inclosed the slate-greenstone country rock. 
Their surf ace exposures are irregular, and though rich ore occurs it does not appear lobe 
uniformly dist ributed, and developments have not yet defined any extensive high-grade ore 
bodies. 
MONTANA CREEK. 
At the head of Mont ana Creek, at an altitude of 2,600 feet, is a basin of considerable area, on 
the slopes of which the Montana Basin group of claims has been located. The rock expo- 
sures at the mouth of the basin are of slate and greenstone, and at its head, or to the east , the 
schist belt occurs. The ore bodies consist of stringer leads or lodes of mineralized slate cut 
by many quartz veinlets. Several such lodes have been uncovered which are parallel to the; 
bed-rock structure, besides two narrow but richer quartz veins striking in a northeasterly 
direction. Four hundred feet of tunneling have been extended at various points on these 
claims, and the assessment work is done each year. The low values in ore bodies and I heir 
distance from salt water has been the chief cause of their retarded development. 
Considerable capital has been invested by the Mansfield Cold Mining Company in the 
development of a group of both lode and placer claims on the south side of McGinnis Greek, an 
eastern tributary of Montana Creek, but apparently with unsatisfactory results. On the 
lode claims several stringers of quartz were followed by tunneling and found to be of no 
value. The placer claims are located on an extensive bench deposit, which contains con- 
siderable slide rock from the high cliffs above them and has a large percentage of heavy 
bowlders and cobbles. Tests made on this deposit have determined that the values are not 
great enough to warrant further exploitation. 
