6

diorite cut the sediments here and there from Kitsumgallum lake east to
Seven Sisters mountain. On Maroon mountain the axial planes of the major
folds strike east and the sediments have local dips as high as 70 degrees,
but the average dip is only 30 or 40 degrees. For 15 miles between mount
Couture at Kitsumgallum lake and Ritchie station on Skeena river the
sediments are only slightly disturbed, with dips seldom greater than 10 or
15 degrees. On Seven Sisters mountain the sediments dip away in all direc-
tions from a central granitic core, the dips ranging from 30 to 55 degrees.

CRETACEOUS SEDIMENTS

The name Skeena formation was given by earlier writers to a series of
sedimentary rocks comprised of argillite, sandstone, and conglomerate, with
occasional interbedded coal seams. The distribution of these rocks in the
vicinity of Telkwa and Smithers and north of Kitsumgallum lake is shown
on the Prince Rupert map-sheet (Map 278A). The formation was assigned
to the Cretaceous age on a basis of fossil evidence. As these coal-bearing
rocks were usually found in valleys, they were described as remnants of
an extensive formation largely removed by late Cretaceous and Tertiary
erosion.

During the 1936 season some well-preserved fossil plants of Lower
Cretaceous age were secured on the farm of E.S. Tordiffe about 1 mile
northeast of Cedarvale. The fossils occur at an elevation of 1,000 feet in
a bed of argillite 1 foot thick between massive beds of sandstone striking
north 75 degrees east and dipping 55 degrees northwest. W. A. Bell of
the Paleontological section of the Geological Survey identified the follow-
ing plants from the collection:

Coniopteris sp.

Cladophlebis sp.

Sagenopteris mantelli (Dunker)

Ptilophyllum sp. cf. Pterophyllum aequale Ward (non Brongniart)
Ptilophyllum (Dioonites) dunkerianum (Goeppert) .
Elatides curvifolia (Dunker) Nathorst

He states: “This flora regardless of certain Jurassic elements is inferred
to be probably Lower Cretaceous in age and to be homotaxial with that
from the Luscar formation or from the lower part of the Blairmore forma-
tion in Alberta.”

The strata are northwest of and at the foot of Seven Sisters mountain,
and as the sediments all strike northeast and dip from 40 to 55 degrees
northwest on this side of Seven Sisters mountain it follows that the fossil
horizon stands very high in the stratigraphic succession. The fossiliferous
strata if projected upward along the angle of dip pass well above the top of
the nearest mountain.

On the southwest side of Seven Sisters mountain about 6 miles south-
east of Cedarvale a second fossil collection was made at an elevation of
4,800 feet, where fossiliferous argillite. beds from 1 to 2 feet thick occur
about 100 feet below a prominent conglomerate horizon about 50 fect in
thickness. The strata in the vicinity strike north and dip from 30 to 35
degrees west. W. A. Bell submits the following report on the collection: