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26 B GEOLOGICAL SURVEY OF CANADA

Chione, sp. indt. Two specimens,

Tapes staminea, Conrad. The most abundant shell in the collection.
It is abundant, in a living state, on the N. W. coast, and Mr.
Gabb says that in California it is found in the Post Pliocene,

Pliocene, and Miocene.

Sazxidomus. Species undistinguishable. The outer layer of all the
specimens, which are not numerous, is entirely exfoliated.

Cardium. One exfoliated valve. Appears to resemble C. island-
acum.

Cardium, Several valves of a species which may be referred to
C. blandum, Gld.

Arca Microdonta, Conrad. An extinct species, found so far only
in the Miocene and Pliocene of California. Two specimens,

Axinea, Possibly a form of A. patula, Conrad, but barely dis-
tinguishable from the smooth form (var. Subobsoleta, Carpen-
ter) of the living A. septentrionalis, Middendorf, of the N. W.
coast. Four single valves.

THE CRETACEOUS OR COAL-BEARING ROCKS.

The Cretaceous rocks of the island comprise a considerable  thick-
ness of shale, sandstone and conglomerate with thin limestone bands,
the measurement of which, in the faulted condition of much of the
strata and the absence of good sections, it is difficult to calculate.
The Cretaceous rocks have an exposed breadth along the north shore of
Skidegate harbour of about ten miles, namely, from the point west of
Skidegate post-office, or what is known as the oil works, to the old
Cowgitz anthracite mine.

Northward, they extend along the eastern flank of the mountain range,
composed of pre-existing igneous rocks, probably to the mouth of Masset in-
let, where the village of Masset is situated; but since the greater portion of
this area is covered with timber and soil, and exposures are almost en-
tirely absent, the exact line of demarcation cannot be definitely determined
beyond the fact that they do not appear to occur west of Masset inlet, with
the exception of a small outlier near the south end of North island, at the
extreme northwest corner of Graham island. The most northerly outcrops
of this formation seen in the interior of the island were certain exposures
of sandstone on the Yakoun river, about midway between the lake at the
head and the upper end of the inlet; and of sandstone and conglomerate
at the mouth of the Nadu river, which enters the inlet about twelve miles
from the village of Masset. Similar exposures are also seen in the
channel east of the large island about one mile south of the Nadu.