piundle.] GEOLOGIC SKETCH. 33 
the Seventymile. Precipitous slopes were seen nearly 2 miles to 
the north across Seventymile. These were not visited, but in the con- 
tinuation of these slopes a few miles to the west the same formation 
was found. The maximum size of pebbles observed in the conglom- 
erate was 5 inches ; the average was from 1 to 3 inches. The material 
is mostly black, gray, and green chert, quartzite, and vein 
quartz. The rock grades into a sandstone containing black chert 
pebbles in a sandstone cement resembling mortar. All the way to 
Barney Creek the ridge on the north side of the river is made up of 
this formation, either nearly vertical or dipping steeply toward the 
valley. The cement contains much ferruginous matter, and the rock 
breaks down easily into its constituent materials, which form loose 
heaps of gravel and sand. The strong, abrupt spurs on the south of 
Seventymile are also of this material as far as the falls. The steep- 
ness of the dip is well shown in the nearly vertical position of the 
leaves so abundant in the shale. 
On the west side of Mission Creek, about 2 miles above Excelsior 
Creek, there is a bluff 150 feet high of similar conglomerate, com- 
posed mostly of chert and vein quartz. Some pebbles of quartzite- 
schist were seen. Brownish sandstone is associated with it and fer- 
ruginous nodules, both containing the same species of plant life that 
were found on Bryant Creek. The dip is 50° to the northwest. 
A similar conglomerate occurs on Wolf Creek, about 1J miles above 
its mouth, forming a bluff 125 feet high on the west side of the creek. 
The occurrence is very similar to that on Mission Creek; the con- 
glomerate varies to a brownish sandstone, and its pebbles are mostly 
black and red chert and vein quartz with occasional pieces of granite 
and diorite. Some of the rock weathers easily and some is com- 
pact, like that of Seventymile. About 4 miles above the mouth of 
Wolf Creek, in the valley of a small tributary from the west, occur 
conglomerate, brown sandy beds, and clay. There is some associated 
coal, loose pieces of Avhich, a foot or more in diameter, were seen at 
the head of the creek; a few shallow prospect holes had been sunk 
to determine its amount. The coal contains grains of soft, brittle 
amber. Nodules similar to those on the Seventymile were found 
which contained ill-preserved plant remains correctable probably 
with those of the Seventymile. The low ridge directly south of 
Eagle is also composed of conglomerate, which continues for 4 miles 
southwest from Eagle, on the trail to American Creek, up to an alti- 
tude of about 2,000 feet. This is probably an extension of that on 
Wolf and Mission creeks. As in other localities, the conglomerate 
>reaks down easily into constituents, and the gravels thus formed may 
eadily be mistaken for more recent deposits. Conglomerate occurs 
igain about half way between the mouth of Excelsior Creek and Gla- 
Bull. 251—05 m 3 
