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basalts of Mount Etheline were in 1913 thought to belong to this
formation, and the name was given for this reason, in the writer’s
Summary Report for that year. Field work in 1914, aided by
study of the rocks in thin section, made it evident that the basalt
flows of Mount Etheline and elsewhere in southern Graham
island are to be correlated with the Masset formation, of
later Tertiary age. The formation name Etheline is thus res-
tricted to intrusive volcanic rocks. No effusive types have been
recognized as belonging to this formation, although it is possible
that they may occur.

Distribution. Dykes and sills are of frequent occurrence
over virtually all of southern Graham island. They are partic-
ularly abundant in the rocks of the Vancouver group, so that
in some localities as on King, Canyon, and other creeks, the
intrusive rocks occupy areas as large or larger than does the in-
truded formation. There is thus a marked tendency for the
older formations to contain the intrusive rocks in greater abund-
ance than the younger ones; and this is the case even in the
Queen Charlotte series, where few dykes or sills penetrate the
Honna conglomerate.

In the vicinity of Parry passage, between Langara and
Graham islands, are numerous intrusive rocks, which on account
of lithological similarity are correlated with the Etheline intru-
sives. Lucy island, and the larger part of Cape Knox consist
of one of these intrusions of biotite andesite, in the shape of a
huge dyke, which is at least a mile wide, and 5 miles long.

Lithology. In composition the dykes range from dacite to
basalt, and virtually all the volcanic rocks of the series are re-
presented in dyke form, while all but the dacites are represented
as sills.

The determination of the several types is next to impossible
in the field. The dacites and quartz-bearing andesites are light
coloured rocks, generally pale grey, and are characterized usually
by phenocrysts of quartz and plagioclase. The andesites are
similar, but lack the quartz. The augite andesites and basalts
are darker grey rocks. All the rocks show porphyritic facies
and the groundmass is in every case very fine-grained. Most
of them are characterized by finely divided, disseminated pyrite.