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Dykes of diorite are very plentiful in the sediments on the shores of
Alice arm near the contact of the batholith. They were not studied in any
quantitative way, but the general impression was gained that the dykes
nearer the batholith took on more and more the look and mineralogy of
the batholith itself. If this were an established fact it would indicate that
the batholith was the source of the dykes. Dykes are common even at
the head of Alice arm 4 miles from the contact.

Dykes appear to be more plentiful in the western half of Alice Arm
district than in the eastern half and this would be a natural result if the
batholith were the source of all dykes because they probably would be
more numerous nearer it than farther away. On the other hand dykes
appear to be less plentiful in the Copper Belt than elsewhere in the Kit-
sault body, thus suggesting that some of the dykes may be related in origin
to some part of the Kitsault igneous body.

One dyke of fine-grained gabbro or basalt crossing Illiance river in
the vicinity of Table mountain closely resembles the Tertiary lavas in gen-
eral appearance and in mineral composition. It is suggested that this
dyke is associated in origin with the Tertiary lava and may have been,
indeed, a feeder of the flows.

Several dykes of augite porphyrite occur in association with larger
bodies of the same rock. A dyke of augite porphyrite that occurs west of
LeRoy mountain differs somewhat in general appearance from the larger
bodies of augite porphyrite, but probably was derived from the same
magma. A dyke on McGrath mountain consisting of acid plagioclase,
orthoclase, and hornblende may be related to the augite porphyrite even
though it differs in containing hornblende instead of augite.

Fine to coarse-grained dykes with a diabasic texture are fairly com-
mon in various parts of Alice Arm district. They are in general large
dykes, 10 to 100 feet wide, and are known locally as diabase or diorite
dykes. They consist chiefly of augite and labradorite. Some contain
hornblende and some orthorhombic pyroxene. In some the plagioclase is
andesine.

Some dykes very closely resembling the diabase or diorite dykes
proved to be more acid types. They contain oligoclase-andesine, horn-
blende, and some orthoclase. It is quite probable that these are related
to the diabase dykes and that all intermediate phases exist. The writer
is inclined to believe that these dykes are related to the Coast Range in-
trusives. This belief is based only on indirect evidence. They do not
resemble the Hazelton group igneous rocks as they probably would if they
originated from them.

Dykes ranging from aplite to granodiorite occur but are not clearly
one series. Aplitic dykes are uncommon. One near the wharf at Alice
Arm is a white dyke containing small quartz and albite phenocrysts in a
very fine-grained groundmass of muscovite, feldspar, and quartz. Another
very light-coloured dyke proved to be a quartz porphyry and of somewhat
coarser grain. These dykes may be related to the Coast Range intrusives.

The commonest dykes are known as lamprophyre dykes. They are
younger than the quartz diorite dykes and commonly also younger than
the mineral deposits. Some are very like the felsites of the district and are