10
AGE AND CORRELATION

‘The ages of the Bitter Creek, Bear River, and Nass formations are
not definitely known. McConnell! could do no more than state that they
“probably range from late Paleozoic to Jurassic.” Schofield and Hanson2
were of the opinion that the Bear River and Nass formations represented
the Porphyrite group of Dawson and were of Jurassic, probably Upper
Jurassic, age. Fossils collected from the base of the Nass formation on
Salmon river represent new species and as yet do not serve as indexes to
the age of the rocks. Fossils have been found in the Bitter Creek forma-
tion on Bear river, but are fragmentary and do not fix the age of the strata.

An attempt was made to trace the Bitter Creek sediments and Bear
River volcanics from Marmot river southeast into Kitsault River basin,
15 miles distant, but the intervening area is largely covered by ice and
snow and, therefore, the attempt failed. In the northern part of Kitsault
River basin3, a thick series of sediments, known as the Kitsault River
formation, and consisting chiefly of black argillites, overlie an assemblage
of volcanic rocks, chiefly tuffs and breccias, and named the Dolly Varden
formation. Fossils were obtained from the basal part of the Kitsauli
River formation, but did no more than indicate that the strata were
“either Jurassic or Cretaceous and very probably Jurassic”. The general
relations existing between the two formations indicate that the lower
grades into the upper without any unconformity. About 15 miles north
of Kitsault River area, the Nass formation is known to be present over-
lying the Bear River voleanics. It seems reasonable to conclude that the
Kitsault River formation corresponds to the Nass formation, and the
Dolly Varden to the Bear River. A possibility exists, however, that two
sedimentary formations have been classed as one in upper Kitsault River
basin. The Kitsault River sediments of the eastern part of the upper
river basin clearly overlie the Dolly Varden voleanics, but though the
same relation seems to hold in the western, upper part of the river basin,
yet southward, as Alice arm is approached, the western band of sediments
appear to tip under the central area of volcanics.4 Furthermore, McCon-
nell® was disposed to think that the southward continuation of this
sedimentary band as displayed on Alice arm corresponded to the Bitter
Creek formation. Thus it may be that the succession in Kitsault River
area is the same as that established in Bear River area and that the

strata in question consist of upper and lower sedimentary formations
separated by a volcanic member.

The possible threefold division of the rocks on Kitsault river is men-
tioned, but is not viewed with favour. In discussion on correlation the
twofold division will be followed. A reconnaissance has been carried 75
miles south from Alice arm to the mouth of Kitsumgallum river on

*Geol. Surv., Canada, Mem. 32, p. 12 (1913).

?Geol. Sury., Canada, Mem. 132, p. 9.

3Hanson, George: Geol. Surv., Canada, Sum. Rept. 1921, pt. A, pp. 7-21 (1922).
‘Unpublished observations of the present writer.

5Geol. Surv., Canada, Mem. 32, p. 83 (1913).