Whitesail Lake Map-Area

volcanic rocks had previously been referred to the ‘Porphyrite group’ of
Dawson (1875-76, p. 250) a term descriptive of their porphyritic texture.
Leach in his work followed these volcanic rocks northward into the Hazelton
area where they gave place to sedimentary strata. It was, therefore, clear
that the descriptive term ‘Porphyrite group’ was not generally applicable
and Leach dropped it in favour of the non-descriptive term, Hazelton group.

Shales and sandstones near the top of the group are partly fossiliferous,
and on the basis of fossils collected the group was assigned an Upper Jurassic
or Lower Cretaceous age.

Lying above the Hazelton group rocks as outlined by Leach in the
Hazelton and Telkwa area and commonly occurring in small patches folded in
with the underlying Hazelton rocks, is a series of coal-bearing conglomerate,
coarse sandstone, thin shaly sandstone and nodular shale. Fossil plants
from these beds were determined by Leach (1910, p. 64) to be equivalent
to the Lower Cretaceous about the horizon of the Kootenai series. The
boundary between the two series of rocks was not a definite but an arbitrary
one (Leach, 1911, p. 93). The Hazelton group as described by Leach did
not include the coal-bearing beds, which were placed in the Skeena series.

Subsequent workers extended the area of Hazelton rocks both south
and north of the town of Hazelton, most fossil collections being made from
Middle and Upper Jurassic sedimentary beds. Some workers found no
unconformity at the base of the Skeena series and included it in the Hazelton
group; others found an unconformity and regarded the two as separate units.
Thus the upper limit of the Hazelton group was left in some doubt. The lower
limit was not defined by Leach, and Hanson (19255, p. 41 A), in the Portland
Canal area, believed that the group included some Triassic rocks.

Hanson (1935, p. 5) reviewed the Hazelton problem as it stood at that
time and said:

There is in the west central part of the province a series of rocks, the
parts of which are in the main conformable, consisting mainly of volcanic rocks
and clastic sediments lying between Paleozoic sediments and the Skeena series,
and for which it is desirable to retain the name Hazelton group. The group
can in many places be divided into parts but in general very few of the rocks
contain fossils of diagnostic value, and therefore their age can be stated only
in general terms. Fossils found in the Portland Canal area indicated that the
rocks were, in part at least, of Jurassic age.

More recent work has been done by Armstrong (1944a, b) in the
Smithers and Hazelton areas, and of the Hazelton group he stated (1944a):

The Hazelton group consists of an apparently conformable succession, pos-
sibly 10,000 feet thick, of interbedded sedimentary and volcanic rocks ranging
in age from pre-Middle Jurassic to Lower Cretaceous and including what have

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