34 COAL EESOUKCES OF THE YUKON. [no- 218. 
ever, several miles up the river from this place, plant fossils, possibly 
Paleozoic, were found. 
The weight of the evidence seems to point toward a Permian age of 
the coal, though it is possible that the beds are of later age, infolded 
and overthrust by the Permian limestone. The following facts point 
to the latter conclusion: 
First. The Eocene coals of this region generally are found in shales 
interbedded with conglomerates which are similar to these, except for 
the extreme crushing here shown. 
Second. There is a great deal of heavy conglomerate and interbedded 
shale along the Yukon in this vicinit} r , varying greatly in the degree 
of consolidation, but showing a general lithologic similarity, and fossil 
plants from some of these rocks have been determined definitely to 
belong to the Kenai formation. 
Third. Both above and below Nation River the sandstones and con- 
glomerates are intensely folded and faulted, and the formations are 
often overturned. A few miles above Nation River, conglomerates 
which are younger than the Carboniferous are overlain by belts of 
Carboniferous age. This relation has been brought about by a thrust 
fault. In this vicinity the conglomerate sandstone series shows an 
overturned fold, which has brought slates believed to be Paleozoic 
above them. A similar explanation may account for the relations of 
the conglomerate and Permian beds at Nation River. 
Fourth. Mr. W. E. Williams, who was manager of the Nation River 
coal mine while it was in operation, reports that in following the coal 
downward the dip became vertical and afterwards overturned, so that 
the dip, which at the surface was to the southeast became northwest- 
ward. 
More extended and more detailed work in this vicinity is required 
to determine definitely the age of this coal. Should it be found to be 
of Carboniferous or Permian age, which seems doubtful, it would be 
important as indicating the possible presence on the Yukon of deposits 
of the older coals. In 1899 Brooks found a series of Carboniferous 
strata about 240 miles southwest of this locality that contained beds 
of impure coal, which he described as follows : a 
Coal has been reported from the region of the upper White and Tanana rivers, 
but during our reconnaissance of the past season we saw no beds of coal which would 
be of commercial value. At a number of places carbonaceous shales of Carboniferous 
age were found, but none of these were sufficiently pure to use for fuel. One of 
these was about 10 miles west of Kershaw Kiver, near our route of travel. At this 
locality beds of carbonaceous material some 20 or 30 feet in thickness were exposed. 
Much of it had been altered to graphite by dynamic metamorphism. Near the 
upper end of Lake Kluane similar beds were found. On Kletsan Creek carbonaceous 
shales containing a little bituminous coal were found, but the coal was too impure to 
have any fuel value. 
a Reconnaissance from Pyramid Harbor to Eagle City, Alaska: Twenty-first Ann. Kept. U. S. Geol. 
Survey, pt. 2, 1900, p. 382. 
