140

due to minor faulting, as a short distance up Anthracite creek,
the massive fine sandstones of the upper Haida lie flat or at low
angles. These beds form part of the large, flat syncline already
mentioned as underlying the country west and southwest of Camp
Robertson.

Yakoun Lake.

Location. Yakoun lake is situated in the southern part of
the island, about 3 miles from Camp Robertson, and 14 miles
from Queen Charlotte by trail. Near the southeast corner of the
lake, where it bends sharply to the west, some prospecting has
been done, and about 24 miles by trail south-southeast of that
point Camp Trilby is located.

Stratigraphic Position. The exposures in this section of the
island are few and little time was available for their study, so
that the stratigraphy and structure have not been worked out
thoroughly. From the data available, however, it is probable
that the coal seam southeast of Yakoun lake occupies a narrow,
north-south, closely folded syncline, pitching to the north.
It is separated from the wider, main syncline of the Honna basin
by an anticline of the older Yakoun volcanics. The relations are
further obscured by Tertiary volcanic flows, but the areal rela-
tions and the structure are believed to be essentially as delineated
on the maps and sections.

The coal seam is apparently not as far above the base of the
Haida formation as it is at Camp Robertson, and the coal
probably represents a lower horizon. It is fairly certain that the
coal of Cowgitz, Slatechuck, and Yakoun lake represents the same
horizon.

Coal Seam. The opening nearer the lake is an adit on the
left bank of a small creek, driven south 60 degrees east for 50
feet across the measures. In it are exposed black carbonaceous
shales, cracked and slickensided, containing lenticular veinlets
of hard, altered, coaly matter one-fourth of an inch thick. At
about 40 feet in from the portal a 3-inch seam of anthracitic
or coky coal is exposed. Above the adit in the creek bank
a 4 to S-inch seam of altered coked coal is exposed, probably