34 FORTYMILE, BIRCH CREEK, AND FAIRBANKS PLACERS, [bull. 251. 
cier Mountain. This may be an independent belt or an extension 
from the main mass. 
In the Chicken Creek area patches of sandstone occur, with asso- 
ciated shale and coal and possibly some loosely consolidated conglom- 
erate. As on Seventymile and Wolf creeks, there are ferruginous 
nodules which contain fragments of dicotyledonous leaves. The 
sandstone and shales also contain plant remains, badly preserved, but 
indicating the relationship of these beds with the Kenai, to which 
they are provisionally referred. 
Until more 3etailed studies are made it has seemed best to correlate 
with the Eocene or Arctic Miocene the rocks of all the localities vis- 
ited, where conglomerate beds occur associated with sandstone, shale, 
and coal. Plant remains are always present, and where determinable 
have been found to belong to this horizon. On Napoleon Creek there 
are conglomerates, sandstone, and coal-bearing beds similar to those 
on the Chicken, which, with those on the Chicken, have been referred 
by Spurr and Schrader ° to the Mission Creek formation. The prob- 
lem of the relations of the younger rocks to the underlying metamor- 
phics and to each other requires detailed work for its solution. 
A deposit on the west side of Mission Creek, about a quarter of a 
mile above the mouth of the Excelsior, unlike any seen elsewhere by 
the writer, was described by Schrader h in Spurr's report. The bluff, 
here 90 feet high, is composed mostly of very slightly consolidated, 
angular, granitic material. Fragments of coarsely porphyritic light- 
colored granite 2 feet in diameter occur. There is much fine material 
of the same nature and a few water-worn pebbles, but apparently no 
chert pebbles. Some thin-layered beds of gray sandstone and clay 
beds with carbonaceous matter occur. The outcrop has a thickness of 
about 30 feet and is tilted with a dip of 50° to the south ; the strike 
is N. 35° W. It is capped unconformably with 20 feet of coarse 
stream gravels. The locality is about 1| miles below the bluff on 
Mission Creek, where the Kenai conglomerate with characteristic 
fossils was found; the nearest outcrop on the north is quartzite-schist 
at the foot of the hill, a quarter of a mile distant. It is referred 
provisionally to the Kenai. 
QUATERNARY DEPOSITS. 
Bench gravels. — Bench gravels are common and attain their great- 
est development near the larger streams. They have been observed in 
many valleys of the Fortymile region and at various heights. The land 
" Geology of the Yukon gold district : Eighteenth Ann. Rept. U. S. Geol. Survey, pt. 3, 
1898, pp. 175-176. 
b Op. cit., p. 339. 
