52 FORTYMILE, BIRCH CREEK, AND FAIRBANKS PLACERS, [bull. 251. 
500 feet farther up by another dike of the same rock. The stream 
gravels are derived largely from the metamorphic formation, but in- 
clude also a considerable proportion of granodiorite and some basalt. 
It is proposed to work the gravels in the drained portion of the river 
bed, which is about 200 feet wide, by a steam dredge during the season 
of 1904. The gravels along the side of the channel are 7 feet thick and 
are covered with about 8 feet of sand and muck, while those of the 
lower benches vary in thickness from 10 to 20 feet. Considerable 
work has been done here, but it is not known whether the average 
values of the gravels have been found sufficient to justify their exploi- 
tation. 
Other localities. — There has been some prospecting in upper Hutch- 
inson Valley. Two men working on Confederate Creek, just above 
the mouth of Humbug Pup, report about 6 feet of gravel on a bed rock 
of schist. Some prospecting was in progress on Montana Creek, at 
the mouth of which good results are said to have been obtained in 
1902. So far as seen the bed rock throughout the valley belongs to 
the schist-limestone formation, cut occasionally by granitic and ba- 
saltic dikes. 
Napoleon Creek was not visited, but is said to carry good values. 
It has been extensively exploited in the past, though little except 
representation work was done during 1903. 
A few men were found working on the bars of Fortymile between 
Steele Creek and Bonanza Bar. The rocks along this portion of the 
river are closely folded hornblende, mica, garnetiferous and quartzite 
schists, interbedded with bluish crystalline limestone, with a uniform 
strike about east and west. 
Nugget Gulch, a small tributary of Fortymile, has its source in a 
dome 3,320 feet in height, about 4 miles north of the river. It flows 
in a southerly direction through a narrow V-shaped valley, and enters 
Fortymile about 2 miles below Steele Creek. This creek is said to 
have produced considerable gold in the early days, but in June, 1903, 
no one was found working on it. The schist-limestone ' formation 
outcrops frequently in the bed of the creek and on the sides of the 
canyon, with a northerly upstream dip. The quartzite-schists often 
show crumpling and even brecciation of the different layers. A 
large mass of basic igneous rock related to gabbro occurs at the head 
of the creek. The gravels include varieties of schist, limestone, vein 
quartz, and pieces of the dark-green igneous rock. The creek has 
been worked for a mile above the mouth, over a width of about 30 
feet. 
Gravels occur on the benches in the vicinity of the Fortymile, and 
as the gulch diggings become worked out attention is being directed; 
" No work was done here during the season of 1904 and the locality at present is 
ehiefly of physiographic interest. 
