6

meanings to the rocks in the other parts of the area and hence are aban-
doned in favour of the more general name Hazelton group. In reports
dealing with Salmon and Bear River districts the names Bitter Creek for-
mation and Nass formation were used to designate what appeared to be
distinct series of sedimentary rocks separated by a volcanic assemblage
designated the Bear River formation. It now appears that there is only
one series of sediments divided locally by large bodies of volcanic rocks.
The group of rocks comprising both sediments and volcanics appears to
extend over the whole of Portland Canal area and is aptly named the
Hazelton group. It is not, however, to be inferred that the whole of the
Hazelton group is represented. Neither the top nor the base of the group
has been recognized in the area and it is not known whether a large or a
small part of the whole Hazelton group is represented. Fossils found in
the area indicate that the rocks are, in part at least, of Jurassic age.

The Hazelton group in Portland Canal area consists of sedimentary
and igneous rocks. In part of the area the sediments form a continuous
series uninterrupted so far as is known by the products of vuleanism. In
most of the area, however, sedimentation was interrupted by one or more
episodes of vulcanism which resulted in the intrusion and extrusion of
igneous matter. Igneous rocks, chiefly of a fragmental nature, occur as
abruptly terminated, lens-shaped bodies many miles long and thousands
of feet thick. These bodies are roughly conformable with overlying and
underlying sediments and are, or have been, completely enclosed by them.
Bodies of intrusive rock are more irregular in shape but are in part sill-
like. They also are surrounded by sedimentary rock. Several types of
intrusives may form parts of a single body.

The sediments were being deposited before vuleanism began and sedi-
mentation continued after vulcanism had ceased. At one or more pro-
tracted intervals sedimentation was interrupted over most of the area and
volcanic rocks were laid down and intrusive counterparts were emplaced.

HAZELTON GROUP SEDIMENTS

The sedimentary part of the Hazelton group includes the forma-
tions designated in earlier reports as the Bitter Creek of Bear River dis-
trict, the Nass formation of Bear and Salmon Rivers districts, the Kitsault
River formation of Alice Arm district, and the Goose Bay formation of
Anyox district.

Sedimentary rocks extend southward and eastward from Alice arm to
Skeena river. South of Alice arm and Illiance river the sediments are con-
tinuous, but to the north within Alice Arm district they are divided into
northerly striking bands by three bodies of igneous rocks named from east
to west the Theophilus, Kitsault, and Klayduc igneous bodies. The Klay-
duc and Theophilus igneous bodies terminate within Alice Arm district
and are, therefore, surrounded by the sediments. The northern part of
Alice Arm district is covered with ice and it is not known whether the
Kitsault igneous body terminates in the north part of the district or con-
tinues into Marmot and Bear River districts. Scattered outcrops of sedi-
mentary rocks north of Alice Arm district make it fairly certain, however,
that the sediments continue north under the ice to join with the sediments