General Geology

Fossil remains were found at numerous localities but those giving best
results were along Tahtsa River, near the east end of Nadina Lake and, on
Troitsa Peak, and Chikamin Range. Fossils were also found on Tweedsmuir
Peak, Mount Sweeney, Nadedikus Mountain, and Holmes Ridge.

H. Frebold and J. A. Jeletzky of the Palzontological section of the
Geological Survey of Canada identified the fossil collections and commented
on their age and stratigraphic significance.

Collections made in the area are as follows:
Northwest ridge of Troitsa Peak

Catalogue No. 13754. H. Frebold
Tmetoceras regleyi Dumortier
“Polymorphites” cf. senescens Buckman
Pleuromya sp. A
Arca sp.
Indeterminable gastropods
Age: Lower Bajocian (early Middle Jurassic)

Catalogue No. 13753. H. Frebold
Tmetoceras regleyi Dumortier
Pleuromya sp. A
Trigonia sp. indet.
“Rhynchonella’ sp. indet.
Gastropods indet.
Age: Lower Bajocian (early Middle Jurassic)

Catalogue No. 13758. H. Frebold
Tmetoceras regleyi Dumortier
Poorly preserved pelecypods (Pleuwromya?) and gastropods
Discinia sp.
Age: Lower Bajocian (early Middle Jurassic)

Frebold (1951, p. 20) remarked that Tmetoceras regleyi Dumortier has
hitherto been unknown in Canada and that it represents an early Bajocian
horizon. Its stratigraphic position is older than that of the widespread Lower
Yakoun fauna (Stephanoceras and Chondroceras) of British Columbia and
its equivalents in the Fernie group of Alberta, but younger than faunas with
Harpoceras, Fanninoceras, and Dactylioceras (found at various places in
British Columbia and Alberta) which, as stated by McLearn, belong to the
Toarcian. As stated previously, this bed is not the bottom of the Troitsa
section but is underlain by volcanic rocks some of which may possibly reach
into the Lower Jurassic.

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