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VANCOUVER GROUP.

Rocks of the Vancouver group make up virtually all of the
surface formations on the islands south of Skidegate inlet, and
on Graham island are with few exceptions found unconformably
underlying the Cretaceous rocks. The Vancouver group is
divided into the Yakoun formation, of middle Jurassic age, and
the Maude formation, referred to the lower Jurassic, and pos-
sibly in part Triassic.

MAUDE FORMATION.

Distribution. The rocks of the Maude formation are typic-
ally exposed on the shores of South bay, and on the south side
of Maude island in Skidegate inlet. They are also the surface
bedrock formation underlying a large area northwest of Camp
Robertson in the Yakoun valley, and on the hills between the
Wilson trail and the Yakoun river, and are extensively rep-
resented west of the latter stream. Representatives of the
Maude formation are found on Frederick island, and the sedi-
ments of the northwest corner of Graham island also are thought
to be of that age.

Lithology. The Maude formation is made up of detrital
sediments, with a few bands of pyroclastic material near the top.
The lower portion is composed of black and brown, fine-grained,
banded slaty and flaggy argillites (Plate XI). These rocks are
highly fossiliferous, and are remarkable for the abundant flattened
ammonites they contain. Many ot the bands are very car-
bonaceous, and where they have been crushed or slickensided,
often simulate coal seams. The ‘‘No. 2 coal mine’ of Richardson
(see page 7) was without doubt situated on a band of this
nature in the argillites. AA marked characteristic of the flaggy
argillites is their strong bituminous odour and films of tar are
found on many of the bedding and joint surfaces.

The upper part of the Maude formation consists of fine,
even-grained, often well laminated, greenish-grey, feldspathic
sandstones. The sandstones are very massive, and tougher and
more homogeneous than those found in the Cretaceous, though
in general appearance they resemble them. Near the top of the