20 FAIRBANKS AND RAMPART QUADRANGLES. 
At the north end of the section, fossils determined as Pennsylvania n 
or Permian were found in a low, outlying ridge overlooking the 
Hats. South of these are black slates and cherts at the base of a high 
ridge, the topmost points of which are quartzites containing occa- 
sional chert pebbles interbedded with red and black slates and some 
dark limestones. The relations with the metamorphics on the south 
were not observed. 
The evidence at hand seems sufficient to justify only the statement 
that in the section from Chatanika River to Yukon Flats there is a 
large area of closely folded rocks, in part of Devonian age and in 
part probably older, flanked on the south by highly metamorphosed 
schists and on the north by shaly slates containing Carboniferous 
fossils. 
In the Rampart region a variety of rocks like those already de- 
scribed is found. These rocks have undergone greater disturbance 
and have been more generally intruded by igneous material. They 
have been closely folded; many of them have been greatly sheared 
and in some places brecciated. The strike of the rocks is nearly east 
and west. The garnetiferous mica schists and marbles of Ruby 
Creek, considered pre-Ordovician, are followed on the north by cherts 
and greenstones and on the south by rocks including slate, chert, 
sheared chert conglomerate, fine-grained rocks having the same com- 
position as the chert conglomerate and also sheared until they have 
been rendered schistose, massive quartzites, and siliceous limestones, 
in places much brecciated. Here, also, the succession seems to be 
from chert and slates through chert conglomerate to fine slate and 
limestone. 
A partial succession has been observed in other localities in the 
Rampart region. The main divide east of Lynx Mountain is com- 
posed mostly of chert flanked by chert conglomerate, and at one 
locality near the southeastern base of Lynx Mountain there are fine 
exposures showing at the base a conglomerate containing sheared 
chert pebbles several inches in diameter, changing gradually to alter- 
nating beds of finer • material. Gray slates, highly folded and 
cleaved and pitching eastward, were observed not far from this 
locality. These slates contain thin beds of quartzite, a few inches to 
a foot or more thick, which contain grains of chert. 
In Troublesome Valley the succession seems to be the same. A sec- 
tion southward between Troublesome and Hunter creeks shows green- 
stones, cherts, sheared chert conglomerate, and slates, with discon- 
nected limestone masses in which fossils determined as Devonian were 
found. The chert conglomerates are at many places found in close 
association with the limestones, and at the locality where Devonian 
corals were collected conglomerate with chert and quartz pebbles is 
