3
PHYSICAL FEATURES

Bear River and Stewart map-areas lie in the eastern part of the
Coast mountains which extend far northwestward and southeastward,
and include all the mountains of the mainland, Pacific coast of British
Columbia. The areas are entirely within the Coast Mountain system,
but the boundary between this rugged tract and the plateau-like, subdued
country to the east passes not far to the east, near the Bear-Nass River
divide. The change from one type of country to the other is fairly
abrupt; steep, bare mountain slopes and alpine peaks give place quickly
to gentler wooded slopes and low, rounded peaks.

The total relief within the map-areas is great. Peaks rise to 7,800
feet above sea-level, whereas Bear river is only 400 feet above sea-level
13 miles from its mouth. The mountain slopes of Bear River valley are
in general steeper than those in the adjacent Salmon River area. Slopes
of 40 degrees for several thousand feet are not uncommon. In Marmot
River valley, particularly on the south fork, the slopes are even steeper,
being over 50 degrees in some places. In this part of the area the valley
sides can be scaled in only a few places.

The north-south valley occupied in the north by American creek and
in the south by Bear river and Portland canal, divides the area in two.
The part west of the valley is a mountain ridge separating Bear and
Salmon rivers and is known as Bear River ridge. The Bear River slope
of the ridge is steeper than the Salmon River slope. The northern part
of the ridge is covered with ice and snow which reaches down the slopes
in several places as short alpine glaciers. The streams draining the east-
ern side of the ridge are very short, have no distinct valleys, but simply .
tumble down the mountain sides.

East of the main north-south valley is a mountainous tract drained
by four principal streams. From north to south these are: Bear river,
Bitter creek, Glacier creek, and Marmot river. Ali four flow westward
to form the main part of Bear river lying in the north-south valley and
draining south into Portland canal. These streams have deeply incised
valleys with normal stream gradients, and enter the main valley at grade.

Much of the eastern part of the mountainous tract is snow covered,
and long glaciers continue down the valleys to low levels. The glaciers
in valleys tributary to Upper Bear river, Bitter creek, Glacier creek, and
Marmot river are short and steep like those in the west of the main north-
south valley. In several places the slopes are so steep and the valleys so
narrow that, in certain times of the year, snow slides down continually in
a narrow stream, building up snow fans in the larger valley. Several such
snow fans form in Upper Bear and Marmot River valleys. Late in July
most of the snow-slides cease, and then rocks tumble down the narrow
gullies. A glacier flows northward into Bear-Strohn Creek valley at the
- low divide between Bear and Nass rivers, partly fills the valley, and
spreads both east and west. Large alpine glaciers exist at the headwaters
of Bitter creek, Glacier creek, and Marmot river, and are kept in motion
by large feeding grounds. Ice erosion has given the area steep-sided,
U-shaped valleys, but the ice has not yet receded far enough to permit
the excavation of large cirques.