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presumably related to them. Most of the so-called lamprophyres are nar-
row, dark-coloured dykes such as are commonly present in British Col-
umbia along the eastern border of the Coast Range batholith. Most of
them may be related to the Coast Range intrusives. An uncommon type,
a minette, occurs in the workings of the Silver Chord group. The dyke
is 2 feet wide and intrudes argillite. It consists of biotite, orthoclase, and
albite. Apatite is a common accessory.

_ While carrying on geological work for the Granby Consolidated Min-
ing, Smelting, and Power Company at Anyox, Bancroft noted that dykes
were more numerous in the argillites than in the amphibolite and that
where the argillites are crumpled, dykes are especially plentiful. Ban-
croft listed the following varieties, named in order of age from youngest
to oldest, as being present.

Dark-coloured basic dykes.

Light-coloured felsites and quartz porphyry dykes.

Dark-coloured diabase, diorite porphyrite, and gabbro dykes.

Dark-coloured augite and mica-bearing dykes.

Light-coloured aplite, pegmatite, and granite dykes.

Bancroft states that in general the dykes are not foliated and, there-
fore, are later than the deformation of the amphibolite and sediments.
They are also later than the ore deposits of the Hidden Creek and Bonanza
mines. He believes that the oldest dykes, the aplites, granite, and peg-
matites, were associated directly with the intrusion of the Coast Range
granodiorite and that the others mark the close of the Coast Range igneous
activity. The present writer did not study the dykes of Anyox district in
detail but did find that some dykes were foliated, and is inclined to believe
that those basic dykes closely resembling the Anyox amphibolite are asso-
ciated in origin with it rather than with the Coast Range intrusives.

Near the edge of the Coast Range intrusives in Anyox, Marmot, Bear,
and Salmon Rivers districts, large dykes and sills of granodiorite and quartz
diorite intrude the older rocks. They are very like the batholith rocks in
mineral composition but most of them are somewhat different in texture,
many of them being porphyritic. On mount Dolly, Bear River district, a
dyke of this type cuts volcanic rocks and can be traced into the batholith
where a short distance from the border it merges with the batholithic rock.

These dykes are obviously associated in origin with the Coast Range in-
trusives.

TERTIARY LAVAS

Basaltic lavas cap Table mountain (south of Alice Arm). Four other
such bodies occur between Table mountain and Nass river and presumably
at one time formed a single body. The rock lies unconformably on older
sediments. The lava is in horizontal beds 10 to 30 feet thick having a total
thickness on Table mountain of 300 to 500 feet. The lava locally exhibits
columnar jointing and the debris at the base of the lava cliffs consists of
hexagonal blocks. The rock is commonly porphyritic. The phenocrysts
are labradorite, enstatite, and augite. The groundmass is finely crystalline
and contains plagioclase, augite, enstatite, olivine, apatite, and black iron

oxide. The rock is locally amygdaloidal, the amygdules containing calcite.
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