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lower American creek the rocks are chiefly tuffs and breccias. On upper
Bear river the rocks are for the most part roughly bedded, but sheets of
crystalline rock are common. On upper American creek and north of
Salmon River district the prevailing rocks are reddish or green to grey
intrusive types of intermediate composition.

In the vicinity of the Premier mine there is a stock of orthoclase por-
phyry 2 miles in diameter. From it sill-like tongues extend north for sev-
eral miles. The stock contains numerous, large inclusions of sheared tufts.
In general the porphyry is fairly even grained and consists of small pheno-
crysts of feldspar and quartz in a medium to fine-grained groundmass.
The rock is highly altered to sericite, chlorite, and calcite, so much so
that in many places the original rock texture has been obscured. Locally,
the rock is strikingly porphyritic and contains phenocrysts of orthoclase up
to an inch in length and smaller phenocrysts of quartz. In some places
the porphyry has been severely sheared and altered and is difficult to
distinguish from similarly sheared greenish tuffs. Ordinarily the porphyry
is grey to light green and is easily distinguished from the darker green
textureless tuffs. The Premier porphyry in texture is much like some
of the reddish and grey intrusive porphyritic rocks, but they are rarely
sheared and have not been so much changed by processes of alteration.
Some facies of the Premier porphyry resemble phases of the Coast Range
intrusives. The writer favours the view that the Premier porphyry is an
intrusive similar in origin to many of the irregularly shaped intrusives
of the Hazelton group and, therefore, that it is of the same general age
as the rocks of the Hazelton group.

Argillaceous sediments occur in minor amount interbedded with strati-
fied tuffs on the east side of American creek and on upper Bear river.
A short bed of limestone up to 100 feet thick occurs in the volcanic rocks
of Marmot River district. The thickness of the bedded volcanic rocks

of the northern part of Portland Canal area is estimated to exceed 4,000
feet.

The rock varieties of the igneous part of the Hazelton group appear
at first sight to be numerous yet in Alice Arm district there are only two
main types, feldspar porphyry (felsites) and augite porphyrite, and the
corresponding fragmental types.

The feldspar porphyry occurring on Klayduc mountain is a greyish rock
with, commonly, small, pink phenocrysts of feldspar. In most places the
porphyry holds rock fragments of the same type as the host. The pheno-
erysts are orthoclase and plagioclase ranging from albite to oligoclase.
The groundmass is fine and granular. Biotite in fine-grained aggregates
occurs locally in the groundmass and muscovite is present in small quan-
tity. Apatite is an accessory mineral. Rock alteration has resulted in
the formation of sericite, calcite, and chlorite. The chief variation is in
size of phenocrysts and in fineness of groundmass. Similar rocks occur
in other parts of the Klaydue igneous body and in many places in the
Kitsault igneous body. Near Kinskuch lake a variety of the porphyry
contains some hornblende phenocrysts. Feldspar porphyry occurs in many
places in the Copper Belt, but in general has been more altered to sericite,
calcite, and chlorite, and contains as well a fair amount of pyrite. The