37

CHAPTER AV.
GENERAL GEOLOGY.
GENERAL STATEMENT.

Regional.

The Queen Charlotte islands, forming as they do a unit
by themselves, can be described only in a broad way with
reference to the geology of the northwest coast of America.
They lie to the west of the axis of the Coast range, along which
denudation has exposed the great batholith, the most impressive
single geological feature of the northwest coast. As they thus
occupy a position on the flanks of the batholith, it would be
supposed that granitic rocks are not abundantly represented in
the group, and such is the case. The areas that occur are small
relatively, and are to be considered as satellitic stocks ‘and
bosses of the enormous mass to the east. The surface rocks of
the Queen Charlotte group are, then, largely either pre-batho-
lithic or post-batholithic. The former are found in large areas
in the islands of the group south of Skidegate inlet; the post-
batholithic rocks being almost wholly confined to Graham
island. In a general way, the pre-batholithic rocks are correlated
with the Vancouver group.

The geological unity of the Queen Charlotte islands is shown
in their fossil fauna, which has provincial characteristics.

Graham island is the northernmost of the group, and a
large part of its suriace is covered with rocks of Upper Cretaceous
and Tertiary ages. In this sense it is geologically the youngest
of the islands.

Local.

The oldest rocks exposed on Graham island belong to the
Vancouver group. They have been divided into two distinct
though gradationally conformable divisions, the Maude and the
Yakoun formations. The former is of lower Jurassic and perhaps

4