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The effect of intrusives, particularly the Coast Range intrusives, on
the sediments has mainly consisted of the introduction of biotite. The
argillites on Alice arm close to the Coast Range intrusives contain augite,
feldspar, epidote, and lesser amounts of hornblende introduced by the
intrusives. At Anyox the sediments have been extensively silicified, and
knotted schists have been formed by the action of the intrusives. In the
vicinity of Tide Lake flats sericite schists are common, but they may have
been formed by compressive forces rather than by thermal metamorphism.

HAZELTON GROUP IGNEOUS ROCKS

The igneous members of the Hazelton group are tuffs, breccias, and
crystalline rocks. They occur in irregularly shaped bodies enclosed by the
sediments, or by the Coast Range granitic rocks, or lie between the Coast
Range intrusives and the sediments. The different bodies may not be of
one age but there is no conclusive evidence to show that they are of very
different ages.

In Alice Arm district there are three main bodies roughly oblong in
shape and with their longest axis parallel to the regional strike of the
enclosing sediments. The three bodies are named from east to west the

Theophilus, Kitsault, and Klayduc igneous bodies.

The Theophilus igneous body is about 30 miles long and 12 miles wide
where widest. It differs from the other two in consisting to a great extent
of fragmental volcanic rocks. The eastern boundary of the body has not
been mapped in any great detail, particularly in the north, but it seems to
follow a much more regular, more nearly direct course than the western
boundary along which in several places the volcanics are interbedded with
seaiments. A small body of augite porphyrite occurs on the south slope of
the most southerly peak of Theophilus mountain. It is intrusive and prob-
ably is a plug or neck of an ancient volcano. Breccias typified by frag-
ments of augite porphyrite and holding perhaps also fragments of flows of
augite porphyrite occur along the western side of the Theophilus body from
Theophilus mountain to Kinskuch lake. The belt is narrow at the south
end but widens rapidly and at Kinskuch lake it is 2 or 3 miles wide. At
the south end it consists of augite porphyrite breccia, but farther north it
contains some fragmental rocks of different type and also rocks that may
be augite porphyrite flows and perhaps also intrusives. Augite porphyrite
breccias and a little augite porphyrite are present on the southern part
of the ridge that extends south from Illiance mountain.

The main part of the Theophilus body consists of tuffs and breccias
in which the fragments are mostly of felsite, tuff, and breccia. Some thin
beds of argillite occur in the bed of Illiance river north of Elevenmile.
They may be interbeds in the volcanic series or they may lie just below the
base of the volcanic rocks at that place. The volcanic rocks are rather
well bedded and, particularly in the northerly trending part of LIlliance
valley, consist to a large extent of partly rounded fragments, amongst
which purplish tuffs and jaspery pebbles are conspicuous. ‘The thickness
of bedded volcanic rocks may be in excess of 3,000 feet. East of the south
end of Kinskuch lake is mount Lavender the highest mountain in the area.
The upper part of it consists of purplish, fragmental volcanics. At the

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