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plateau, swings northeast for 30 miles, and then turns north along or
adjacent to the east bank of Prophet River, which joins the Muskwa 3-5
miles west of the bridge at mile 302. The Muskwa River bridge is about
1,035 feet above sea-level. Adjacent to Prophet River, the Highway
crosses numerous small streams entrenched in valleys several hundred feet
deep. The plateau, which the Highway leaves at mile 201, may be seen
several miles to the east of the Highway as far north as mile 244, The
dissected part of the plateau, with its steeply dipping slopes, has a distinct
mesa-like appearance. A large remnant of the plateau extends northward,
west of Prophet River Valley. South of Trutch Creek the plateau rises
1,500 feet above the bed of the stream.

Pink Mountain, 10 miles west of the Highway in the Beatton River
area, forms a prominent topographical feature that clearly marks the
transition from Plains to Foothills. Its summit, about 5,900 feet above
sea-level or 2,700 feet above Halfway River, is outlined by hard, resistant,
quartzitic sandstone beds, whereas the adjacent, lower lying areas, with
subdued topography, are underlain largely by shale.

ROCKY MOUNTAIN FOOTHILLS

The Rocky Mountain Foothills separate the Rocky Mountains on
the west from the Interior Plains. They occupy a belt that in north-
eastern British Columbia ranges in width from 15 to 40 miles, and is
composed entirely of sedimentary rocks, largely of Mesozoic age, with
some Paleozoic and Tertiary formations. The eastern front of the
Foothills is marked by the first zone of folding and faulting west of the
Interior Plains. Along Peace River Valley the Foothills are well marked
by the upfolding of erosion-resistant Bullhead sandstones and conglo-
merates. Near Sikanni Chief River the easternmost belt of close folding
and the front ridge of hills disappear, so that the width of closely folded
strata is narrowed from there northward, the place of the front ridge
being taken by high plateaux and mesas of more gently dipping Cretaceous
strata.

McLearn’s (1940) description of the Peace River Foothills follows:

“The Foothill belt along Peace River in northeastern British Columbia
is about 40 miles wide, from about longitude 122° 05’ to near longitude
123°10’, that is from Butler Ridge in the east to near Greene Mountain
in the west...

“The scenery, although lacking the grandeur of the mountains, is on
an imposing scale. The relief is high, from about 1,800 to nearly 5,000
feet above sea-level, and the surface is carved into bold and rugged out-
lines. Of particular interest is the variety of surface form. Beside the
river and not more than 20 to 40 feet above it are broad flats, of which,
for example, Branham Flat, triangular in outline, is about 2% miles long
and nearly 13 miles wide. Bordering and rising high above the flats are
high terraces in various stages of preservation, some of which are broad
and continuous for miles. They are only well preserved to a height of
about 500 feet, although what appear to be remnants of older terraces
have been found nearly 2,000 feet above river level. Extending high
above the terraces are steep, high cliffs, long, narrow ridges, and high
hills. The surface form is related to the lithology and structure of the