161

A slight seepage of gas is reported to take place on the shore
of Bearskin bay, west of Queen Charlotte, but this seepage was
not seen by the writer.

ETHELINE FORMATION.

The Etheline formation, composed as it is wholly of in-
trusive igneous rocks, would not be expected to prove a container
of bituminous matter. A single occurrence has been noted
where bitumen fills some of the vesicles in an altered andesite
dyke. The dyke is on King creek about 2 miles above its mouth
and cuts finely laminated, strongly bituminous argillites of the
Maude formation. It strikes north 35 degrees east and dips
40 degrees northwest. The argillites at this point strike north
75 degrees west and dip 60 degrees southwest. The dyke aver-
ages 15 inches in width and is somewhat irregular in outline.
It is dense and in part amygdaloidal; the amygdules are spherical,
up to three-sixteenths of an inch in diameter, and filled with
pale, bluish chalcedony, calcite, or black, hard, tarry matter.
Some of them contain pale brown, viscous oil; and fragments of
the dyke falling in water cause strong iridescent films to form.

The amygdaloidal portion of the dyke is irregularly distribu-
ted through it, generally near its lower contact, and forms less
than 40 per cent of its volume. Where the amygdules are
found the rock is stained pale brown by bitumen; and brownish
streaks and patches penetrate the remainder of the rock, which
is a pale purplish-grey. These streaks are controlled by cracks,
formed after the dyke had consolidated, and the bitumen prob-
ably found its way along them while the rock was still heated.
Very similar brownish stains have been noted in dykes of the
same kind from Skidegate inlet, and their cause was obscure
until this dyke was found.

This is a clear instance of petroleum occurring in an igneous
rock; but it is just as evident that the home of the oil is the bitu-
minous argillites, from which the heated dyke distilled and
absorbed the organic matter.

MASSET FORMATION.

Bituminous matter has been found in the Masset formation
in several localities, which will be described separately.