174 ALASKAN MINERAL RESOURCES IN 1904. [bull. 259. 
examination of the field was undertaken by the United States Geolog- 
ical Survey in 1904. The party for this purpose was landed at Corwin 
Bluff on July 23, and after examining the coast line from Cape Beau- 
fort to Point Hope sailed from the latter point on August 22. The 
party consisted of the writer, who was in charge, Chester Washburne 
and C. J. Hutchinson, held assistants, and Joseph Edge, boatman, alb 
of whom rendered untiring and efficient service and contributed in a 
greater or less degree to the fund of information obtained. 
The important economic result of this expedition is the demonstra- 
tion (1) that the coal fields are much more extensive than has generally 
been supposed, and (2) that there are two distinct coal-bearing forma- 
tions in the region. One of these formations lies east of Cape Lis-i 
burne and contains low-grade bituminous coal of Mesozoic age; the] 
other lies south of the cape and contains high-grade bituminous coal^ 
of Paleozoic age. 
GEOLOGY. 
The hard rock formations of this region fall readily into two groups, 
the Paleozoic and the Mesozoic, whose distribution is indicated by the 
topographic features, since the Paleozoic rocks produce the high relief 
of the Lisburne Range, while the Mesozoic rocks underlie the undu- 
'ating lowlands northeast of these mountains. 
l'ALEOZOIG FORMATIONS. 
Heavy calcareous sandstones and interbedded slates which occur on 
the west side of the Lisburne Mountains constitute what is probably 
the oldest formation of the region. They are exposed in sea cliffs over, 
a stretch of about 15 miles north of Marryat Inlet. The sandstone 
beds range in thickness from 1 to 10 feet, while the slates are usually 
thinner. Their total thickness has not been determined, though it is 
certainly not less than 1,000 feet. The structure consists of a series of] 
broad, open folds, the dips rarely exceeding 30°. Being massive beds, 
the strains to which they have been subjected have been taken up in 
two sets of well-defined joint plains and a slaty cleavage in the softer 
members. The sandstones often present schistose phases and contain 
secondary mica. This formation is Paleozoic, probably pre-Carbonif- 
erous in age, but no fossils have been found in it. 
The sandstone is conformably overlain by a series of slates, shales, 
cherts, and limestones of Carboniferous age, a part of which has been 
called the Lisburne formation." 
These rocks form the sea cliffs from Cape Dyer to a point 3 miles 
east of Cape Lisburne (a distance of about 20 miles), the greater part 
oSchrader, F. C, A reconnaissance in northern Alaska in 1901: Prof. Paper IT. S. Geol. Survey No. 
20, pp. C.2-67. 
