-18=

as is the case in similar limestone-shale relationships farther west;

it may be Triassic, in which case it represents a part, probably a

lower division, of the Triassic section succeeding it to the east. This
last conclusion is the most likely from a structural point of view,

as a Devonian age would involve complicated faulted lteustea eis between
the nDevonian! and Triassic shales.

Rounded, wooded hills of shale flank MacDonald Creek Valley
from mile 110 to mile 125. The shale strikes about northwest by north,
and this determines the direction of the valley. The structure is
principally that of a syncline with limbs dipping at angles from 35 to
50 degrees. In the northern part of the valley the structure is
anticlinal.

In the south flank of MacDonald Creek Valley, between miles
113 and 114, the shale weathers reddish brown to coaly black, and much
black iron sulphate occurs on the surface. Here the shale is crumpled
into a narrow syncline.

» :

At- mile 116, hard, black, cherty rock is exposed in the road-
cut, and the mountain to the east is composed of limy sandstone and
shale. In these the following fossils were found and have been identified
tentatively by A.E. Wilson of the Geological Survey: Productella sp.,
Martinia sp., Athyris spe, and Euomphalus sp, This assemblage indicates
& probable Mississippian age for the beds reopen in the top of the
mountain, which is synclinol in structure.

Slaty beds oceur at mile 1203 and hard sandstone at miles 122
and 124, ,

Hills of pegdish formations rise west of Racing River. In its
eastern bank, at mile 1303, sandstone and shale outcrop ina road-cute .
Productus sp. and Martinia? were collected there, representing a
Mississippian age for these rocks.

Beyond Middle Devonian limestone in the gorge of Racing River,
the Highway crosses alternately shale and dark limestone to mile 143.
The shale is very dark, is generally fissile and soft, and represents
the lower division of the serics. Although no fossils were found in it
the close relationships with the dark limestones suggests a Devonian ogee

Shales are missing from the Highwey to mile 200. At mile 202
in the valley of Trout River hard black shale occurs in the road-cut. At
mile 207, very soft hackly mudstones;with soft sandy beds discoloured with
iron rust, occurs in a road-cut and in an island in Trout River. The
island seems to represent a slumped segment, and the general pons a of
the shale suggests preglacial weathering.

North of mile 211, on the north side of Liard River, round-
topped hills rise to an elevation of about 3,200 feet, or 2,000 feet above
the road. These are composed of brown weathering argillite, sandstone,
and chert thrown into irregular folds, The argillite is sheared, so as
to weather into "pencils" and flakes, No fossils were found on this hill.

On the north side of Liard River, just west of the suspension
bridge, very dark grey, calcareous argillite forms a buttress in the river
bank. In fresh blasted surfaces, the following fossils were found in a
very poor state of preservation: Productus sp», Cliothyridina cf, lata
Shimer, cf. Reticularia pseudolinenta Hall, Brachythyris? sp», Dielasma spe,
Martinia sp., and an unidentiiicd pas gasteropod. This fauna is Mississippian
in age, corresponding rather closely with the Banff shale of the Jasper
Park area, or the middle member of the Banff formation, of the Banff area,
as described by Warren, or the Banff formation of the Moose Mountain-Morley
areas as described by Beach. The. correlation is with the Kinderhook fauna