9

the whole band dips 70 degrees west. North of Klayduc mountain the band
broadens and in the area west of the head of Evindsen creek near the
western side of the band, the sediments lie in a series of small anticlines
and synclines and at the west edge dip west into the Coast Range intrusives.
At the north end of the band, the sediments appear to dip away from the
voleanic rocks of the Kitsault igneous body. |

The strata of Alice Arm district appear to form a northerly striking
anticline about 18 miles wide plunging slightly south at the south end and
slightly north at the north end. The anticline is complicated by several
fairly prominent smaller folds and has been disturbed by intrusions of later
rocks and also to some extent by many minor faults. The thickness of the
sediments in this part of the area is estimated to be at least 3,000 feet.

West of the sediments at Alice arm is a body of the Coast Range
granitic rocks 5 miles or more wide. West of this intrusive, sediments
occur again and occupy the low ground at the junction of Hastings and
Alice arm and in the vicinity of Anyox. These sediments are bounded
on the north and south by granite. They continue about 2 miles west of
Observatory inlet, to where they end against a body of amphibolite. Their
extent southeast of Observatory inlet is unknown. The rocks are mainly
black argillites with, locally, thick beds of greywacke as at a locality a
short distance northeast of Anyox where there is a thickness of 200 feet
or more of greywacke. A few, thin, lens-like beds of grey limestone are
also present. Over most of the area the beds are rather closely folded
into minor anticlines and synclines with no prevalent trend. At Anyox
one sharp anticline is overturned to the east. At the western side of the
area where the sediments are in contact with amphibolite they dip east
at steep angles, and strike parallel to the contact. The strike also parallels
the contact of a small body of the amphibolite partly enclosed in argillite.
In the Hidden Creek mine at Anyox the easterly dip at the surface changes
in a depth of a few hundred feet to a steep westerly dip which seems
to prevail to a depth of more than 2,000 feet. The dips of the sediments
where seen in the mine appear to be concordant with the dip of the
amphibolite-argillite contact. The amphibolite is an intrusive.

The sediments of Anyox district have been greatly disturbed by folding,
in many places have been severely sheared, and locally have been con-
verted into micaceous schist. The rocks have also been altered to knotted
schists containing much biotite, muscovite, and quartz. Locally at the
contact between the amphibolite and argillite the latter rocks have been
extensively silicified. In one place a sedimentary band enclosed in amphi-
bolit has been converted into a very light-coloured, siliceous rock. It
seems probable, therefore, that the amphibolite caused part if not all of
the silicification of the argillites, but judging from the general resemblance
of the metamorphosed argillite of the Anyox district to that near the
granite contact at Alice arm, it would seem that the general thermal meta-
morphism which resulted in the production of knotted schists was caused
by the Coast Range intrusive.

As already stated, isolated outcrops of sediments continue northwest
from the head of Kitsault river to Marmot river where they have been
described as the Bitter Creek formation.1 The sediments of this north-

1 Hanson, George: “ Bear River and Stewart Map-areas, Cassiar District, B.C.”;
Geol. Surv., Canada, Mem. 159 (1929).