ye

continues in this direction for 55 miles. For the greater part of
this distance it follows a high west-facing scarp that parallels

the mountains 12 to 18 miles to the west. The top of the scarp,
which has a plateau~like appearance from the west, is dissected by
east-flowing rivers and streams including the Beatton, Sikanni Chief,
Buckinghorse, and Prophet Rivers. The height of land between the
Peace and Fort Nelson drainage systems lies between Beatton and
Sikanni Chief Rivers and close to mile 108 on the road. The original
army road in this area follows the top of the scarp across the divide
and attains an elevation close to 4,200 feet a short distance north
of mile post 106, the highest point along this section of the road.
From there the elevation drops to 2,662 feet above sea-level at the
Sikanni Chief bridge, North of Buckinghorse River the scarp has

trop of deck over first pier.

an average elevation of 4,000 feet, and is approximately 1,000 feet
above Minaker River to the west. At mile 152 the road leaves the
plateau, swings northeast for 30 miles, and then follows along or
adjacent to the east bank of Prophet River, which flows almost due
north to join the Muskwa 3.5 miles west of the bridge at mile 253.
The elevation of the Muskwa River bridge is about 1,035 feet.
Along Prophet River the road crosses numerous small streams en-=
' trenched in valleys several hundred feet deep. The plateau, which
the road leaves at mile 152, can be seen several miles to the east
of the Highway as far north as mile 195. The dissected part of
the platéau with steeply dipping slopes has a distinct mesa-like
appearance. A large remnant of the plateau can be seen to extend
northward, west of Prophet River Valley. South of Trutch Creek the
plateau is 1,500 feet above the creek,

Pink Mountain is a prominent topographical feature
east of the front range of the Rocky Mountains and about 10 miles
west of the Highway in the Beatton River area. The summit is about
5,900 feet above sea-level, or 2,700 feet above Halfway River. It is
outlined by hard, resistant, quartzitic, sandstone beds, whereas the
adjacent, lower lying areas, with subdued Randa ne are underlain
Leal by shale.

PHYSI OGRA PHY

The region traversed forms parts of three physiographic
divisions; an eastern or Plains province underlain by flat-lying or
gently folded beds and extending for several miles west of the High-
way between Beatton and Prophet Rivers; a western, mountainous province
of folded and faulted resistant strata; and an intermediate, transitional
or Foothills belt of folded strata having moderate relief and a width
of from 6 to 8 miles. Klingzat Mountain marks the eastern limit of the
western, mountainous province; Pink Mountain lies within the inter-
mediate belt; and the eastern province includes a plateau~like area
that extends east of the Highway.

The western, mountainous province was investigated for
12 miles along Sikanni Chief River. The mountains there have a relief
of about 3,000 feet and are composed mainly of Triassic strata and
some Jurassic and Cretaceous beds. Higher mountains formed of
Palaeozoic strata lie to the west, but were not investigated. The
southward continuation of this eastern mountainous belt has been in-
cluded with the Foothills belt along Peace River by McLearn (1940),
but owing to its high relief in the area under present consideration
the writer prefers to consider it as part of a mountainous province.
Structurally it exhibits a series of large folds and some thrust faults.
The resistance to erosion of the Triassic beds is an important factor,
accounting for the relief in this unit.