46

The Maude formation is unconformably overlain by the
Haida member of the Queen Charlotte series on Yakoun river,
Hidden creek, Ghost river, King creek, Tlell river, north of
Camp Robertson, and at other localities. Pebbles of the ar-
gillites are contained in the Honna conglomerate, and in a basal
conglomerate of the Haida formation at the southwest end of
Yakoun lake.

The Maude argillites are intruded by coarse-grained green
diabase in large masses, perhaps of batholithic affinities, along
the south shore of South bay.

Origin. The fauna of the Maude formation clearly shows
it to be of marine origin. The marine origin is also borne out
by the regularity of the beds, their well marked banding, and
their fine grain. The limestones, provisionally correlated with
the formation, are also marine; but largely, if not wholly,
detrital in origin. The large amount of fresh plagioclase through-
out the rocks, and the fine tufaceous material in them indicate
that parts of the formation at least, and certainly the upper
beds, are of pyroclastic origin. Forming, as they do, an inter-
calation in a thick volcanic series, this origin is not surprising.
The fineness of grain, and the abundance of organic remains
point to their accumulation in a sedimentation zone of moderate
depth. Their present induration has been explained as the result
of pressure without shearing, caused by dynamic metamorphism,
and their frequently greatly contorted character as the result
of localized stresses.

Age. On the basis of the determination of its fossils by
Dr. T. W. Stanton, the Maude formation is assigned to the lower
Jurassic. Doctor Stanton writes in regard to the list of fossils
from the formation given below:

‘“‘In my opinion these fossils are of Jurassic age—probably lower Jurassic.

They evidently represent the group of fossils, described by Whiteaves, from
Maude island, which Dawson referred to his ‘Division E.’ ”

Fossils from the Maude Formation.
Brachiopods.

Rhynchonella maudensis Whiteaves ?
Rhynchonella ? sp.
Discina semipolita Whiteaves.