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Sikanni Chief Valley

About 900 fect of light and dark grey, mostly crystalline, partly
crinoidal and dense limestone, interbedded with chert and siliceous lime-
stone are described by Hage (1944) in Sikanni Chief Valley (See Figure
3). These beds outcrop along the crest of an anticline crossing Sikanni
Chief River about 2 miles west of Mount Withrow. Corals, brachiopods,
a gastropod, and a trilobite of Mississippian age, identified by Alice E.
Wilson, are recorded by Hage (1944).

Alaska Highway

Williams (1944) has described the Mississippian beds of the Alaska
Highway under two headings ‘Devonian and Mississippian’ and ‘Mississip-
pian and later?’. Fossiliferous rocks of Mississippian age in the upper
part of his ‘Devonian and Mississippian’ section include: “hard, black,
cherty rock” in a road-cut, and limy sandstone and shale on the mountain
to the east, near the highway along McDonnell Creek, all with brachiopods
of probable Mississippian age; sandstone and shale, with brachiopods of
Mississippian age in a road-cut on the east bank of Racing River, above
the mouth of McDonnell Creek; and “very dark grey, calcareous argillite”’
with Productus and other brachiopods of Mississippian (Kinderhook) age
and correlated “rather closely with the Banff shale of the Jasper Park
area’’, on the north side of Liard River just west of the suspension bridge
over the Liard.

Some unfossiliferous shales and sandstones outcropping along the
Alaska Highway between McDonnell Creek and the Liard River bridge are
described by Williams under the heading of ‘Devonian and Mississippian’.
They include slaty beds and hard sandstone in the valley of McDonnell
Creek; hard, black shale in a road-cut in the valley of Trout River; and
“soft, hackly mudstone, with soft sandy beds discoloured with iron rust?’
in another road-cut and on an island in Trout River.

Other unfossiliferous rocks, mostly shales, argillites, and sandstones,
outcrop in places along the Alaska Highway west of the Liard River bridge,
and include brown weathering argillite, sandstone, and chert, on the north
side of Liard River, just west of the bridge; black, rusty weathering shale
on the highway, east of Smith River; grey-blue sandstone on the north
bank of Liard River west of Whirlpool Canyon; shales and sandstones
west and north of a series of limestone ridges east of Irons Creek; and
soft, banded shale and black, hackly shale near Hyland River. Williams
considers whether these unfossiliferous beds should be placed in his ‘De-
vonian and Mississippian’ unit or whether they are more akin to the
Ordovician graptolite-bearing shales on Dease River, described many
years ago by McConnell (1891). He concludes that the “shales along the
lower Dease and upper Liard Rivers... .do not suggest graptolite shales
to the author, and their rather close resemblance to the more easterly
outcrops makes it seem desirable to include them tentatively with the
Devonian-Mississippian series’’.

_ Williams’ ‘Mississippian and later’ strata overlie his ‘Devonian and
Mississippian’ section and include more limestones and calcareous rocks.
They underlie only a small area and are part of a narrow band of late
Paleozoic rocks crossing the Alaska Highway from mile 380 to 382-5.