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rock types present. The ridge between Portland canal and Georgia river
appears to be underlain mostly by crystalline rocks, but some fragmental
rocks associated with siliceous sediments occur near the head of Georgia
river. In the valley of Georgia river the rocks appear to be mostly if not
entirely crystalline types. At the higher elevations in that part of the body
between upper Georgia river and its south fork there are some argillaceous
sediments striking north and northwest and dipping west. For the most
part the crystalline rocks are coarser in grain than the felsites of Alice
Arm district and appear to be somewhat more basic. Locally the rock is
medium grained and resembles some facies of the Coast Range intrusives.
The body has been intruded by Coast Range intrusives and has, therefore,
been mapped as part of the igneous rocks of the Hazelton group.

The most southerly outcrops of igneous rocks of the Hazelton group
in Marmot River district are several miles from the most northerly out-
crops of the Kitsault igneous body. As the Hazelton group igneous rocks
form only a narrow band in the southern part of Marmot River district
it may be that they do not continue much farther southeast and that they
are not a northward prolongation of the Kitsault body. The northern
body of these igneous rocks is of very irregular shape and includes all
the volcanic rocks of Portland Canal area from Marmot river northward.
The body consists of tuffs, breccias, lava flows, intrusive rocks, and thin
beds of argillite, quartzite, and limestone,

In Marmot, Bear, and Salmon River districts the prevailing volcanic
rock types are breccias and tuffs. Flows and intrusive bodies are not so com-
mon. as in other parts of Portland Canal area. The rocks whether massive
or fragmental are commonly grey or green or else are purple, red, or brown.
The greenish rocks probably owe their colour to chlorite, and the colours
of the purple, red, and brown rocks appear to be due to the presence of
iron oxides. The flows and fragmental rocks are not easily distinguished
from one another as some breccias appear to have a flow matrix and some
flows contain numerous fragments. Individual flows or beds do not con-
tinue far and they merge into the adjoining volcanic rocks. The red types
and the green types merge into one another regardless of whether they are
fragmental or massive varieties. Breccias with reddish fragments in a
green base also occur. The tuffs are mostly of intermediate grain, but
some are fine-grained resembling chert. Some breccias contain many frag-
ments of augite andesite. The lava flows range in composition from augite
andesite to rhyolite but the common type is andesite. Rhyolite occurs
locally and is fairly plentiful in the vicinity of the Porter Idaho mine.
Augite porphyrite occurs as a small body in the southern part of Marmot
River district and in larger, rounded bodies and elongated masses several
miles long in the eastern half of Bear River district. A stock of augite
porphyrite occurs north of Long lake in Salmon River district. More basic
types of intrusive rock resembling the Anyox amphibolite are present in
Bear River district but are uncommon. Coarse, fraemental rocks are com-
mon on Bear River ridge. In the vicinity of the Premier mine and also in
the central and lower part of Bear River valley the volcanic rocks are fine-
grained tufis that have been sheared and converted in part into chlorite
schists. On big Missouri ridge and also farther east in the vicinity of