44 COAL RESOURCES OF THE YUKON. [no. 218. 
and other mammals, but shells of fresh water and land gasteropods, 
represented by species now living, and cones of Picea resembling the 
present spruce of the Yukon Valley, which show that the silts are 
of Pleistocene or late Pliocene age. The material in these bluffs is 
mostly extremely fine silt, greenish gray in color, forming when wet a 
fine sticky clay and showing scarcely any traces of stratification. At 
intervals in this deposit there are thick beds of vegetable material 
containing wood in all stages of change from pliable sticks to brittle 
brown lignite. These beds vary in thickness and also in the nature of 
their material; usually, however, they contain trees, some of consid- 
erable size. 
Near the upper end of the Palisade Cliffs a tunnel has been run on 
one of the lignite beds. In the summer of 1902, however, this tunnel 
had caved in. and the bed could not be examined underground. Mr. 
N. H. Wood/' assistant engineer, U. S. Revenue-Cutter Service, is 
authority for the statement that a vein 20 feet thick was reported here. 
The lignite from this locality is of inferior quality, scarcely changed 
from wood or peat. Where examined by the writer this peat is mixed 
with red sand. Samples Avere taken, but no analyses of them have 
been thought necessary, as in the present stage of Alaskan develop- 
ment these beds have no value. 
Cantwell River. 1 — This river is tributary to the Tanana from the 
south, about 130 miles from the Yukon. The Cantwell has its source 
well within the Alaskan Range, which it leaves through a narrow valley 
cut into metamorphic rocks. The front of the range is about 40 miles 
from the Tanana. At the northern flank of the mountains these met- 
amorphic rocks arc mantled over by coal-bearing, friable sandstones, 
which find topographic expression in a series of low hills running 
parallel to the front of the range. Pathologically the rock is chiefly 
soft, friable sandstone, often of an almost snow-white color, with some 
intercalated conglomerate and shale strata. The basal beds are usually 
conglomeratic. The entire series probably measures several hundred 
feet in thickness. Pathologically it closely resembles the Kenai beds 
exposed near Rampart on the Yukon. The series is either entirety 
undisturbed or is thrown up into broad, open folds. Faulting was 
observed at several localities. 
The coal-bearing beds outcrop for about 15 miles along the river, 
and were traced about 4 miles to the east. The area of this coal 
field can be safely estimated at 60 square miles at least, and may 
be many times that. The beds are seldom exposed except along the 
river and stream valleys, for elsewhere they are usually deepty buried 
under Pleistocene gravels. These coal-bearing terranes were proba- 
ta Brooks, Coal resources of Alaska: Twenty-second Ann. Rept. U. S. Geol. Survey, pt. 3, 1902, p. 557. 
''This note was furnished by Mr. Alfred H. Brooks, in advance of the publication of his report to be 
entitled, "A Reconnaissance in the Mount McKinley Region, Alaska. " 
