a5
River will shed further light on the geological section.

The superficial deposits of the eastern plains are sand and
shallow muskeg. For 57 miles west of Fort Nelson gravel is lacking,
ond sand and silt are dominant except where overlain by shallow muskeg
swamps. The ‘peat ond muskeg conditions are not deep, however, and
exist only because of the flat nature of the uplands and the long
seasonal periods during which frost prevails in the ground.

The Foothills Belt

On the west side of the valley of Kledo River, near mile 50,
the Alaska Highway enters the Foothills belt, which extends westerly
to the front of the Rocky Mountains at mile 101.

Westward from mile 50, the Highway rises between nearly flat-
lying sandstone and shale hills. Beyond mile 52 the dip is westerly,
but the direction is reversed near mile 60 (old road) in a number of
prominent flat-topped hills. Of these, Steamboat Mountain, with its
overhanging cliff on the east side, is most prominent. Its plateau
summit has an elevation of about 4,800 feet, and is a remnant of a
former land surface. Other similar remnants are preserved in Table
Mountain to the north, Teepee Mountain to the east; and hills to the |
southeast, as for instance at mile 8, and between the valleys of Muskwe
and Prophet Rivers.

The range of hills represented i Steamboat and Table Mountains
borders the eastern side of the wide and extensive valley of Mill Creek,
which crosses the Highway near mile 67. To the westward the Highway
crossés sand and shallow muskeg and approaches Tetsa River at mile 85. —
At mile 77. slumping sandstone is exposed in the road cut.

At mile 86% black, Benth, shale. is exposed in the. road out and.
‘a fault separates shale segments that dip respectively 66 degrees east
by north and 77 degrees west by south. Near mile 86, flat-lying beds
contain Cardium, and near mile 865 hard siltstone dips 35 degrees to
the west. Near mile Gis dark shale dips to the south by east at 23
degrees, and at mile 87s hard, coarse sandstone dips easterly at 60 .
degrees. This marks the eastern flank of a prominent anticline with
its western flank near mile 89. The axis is only slightly west of mile
88 and its strike is approximately south 50 degrees cast. The anticline
4s clearly defined south of Tetsa River in the form of-a hogsback ridge,
conveniently. sectioned at intervals by erosion channels. On the west
flank vertical beds occur, and the geology both on the east and west. -:
flanks suggests crumpling and faulting. The rocks. exposed on the anticline
are of Triassic age. ie

_ Near mile 892 sandstone beds contain Ostrea and black crumpled
shale outcrops to the south of the forks of Tetsa River.

At mile 91, vertical quartzite and limestone are exposed in a
road cut, the latter containing a rich Productus fauna. The outcrops
mark the southern end of a range of hills that include, between inile 91s
and mile 92, sandstone and limestone beds of Mississippian and (?) later
age overlain by a series of black chert beds that are probably of Penn-..
sylvanian or Permian age. This belt of Upper Palacozoic formations strikes
approximately south 30 degrees east. It is evidently a block thrust up
from the west over and against the Triassic beds to the east. On its
western side this block is faulted and its bedding planes are disturbed
and quite unrelated to the structure of the overlying Triassic beds.

Hills to the north of mile 93 and mile 94 are crowed by black
limestones and limy sandstones of upper Middle Triassic age. The beds
have dominant westerly dips varying from 30 to 68 degrees. They represent