Landforms of British Columbia 1976 - Department of Geography

iver in pre-Pl&ocene time or whether it was established when the pro-glacial lake
in the vicinity of Prince George was drained. It is possible that during the last stage
of the disappearance of the ice, sufficient ice existed from Summit Lake northward
to prevent the resmnp~ion of flow in that direction. Drainage, as a consequence,
would then have been forced to escape southward from Prince George. At Prince
George the channel of the present river now is some 700 feet below the upper level
of the glacial-lake clays ($a p, 110 for further discussion).
[References: Armstrong, J. E., “ Fort St, James Map-area,” Geol, Swv., Can-
ado, Mem. 252, 1949; Armstrong, J. E., Map 980~, “ Carp Lake,” Gal. Surv.,
Canada: Tipper, H. W., “Prince George,” Geol. Surv., Canada, Map 49.1960;
Tipper, H. W., “ Quesnd,” Gad. Sm., Canada, Map 12-1959; Muller, J. E., and
Tipper, H. W., “ McLeod Lake,” Geol. Sure., Canada, Map 2-1962; Lay, Douglas,
“ Fraser River Tertiary Drainage-history in Relation to Placer-gold Deposits,” B.C.
Depf. ojh’hq Bull. No. 11 (Part II), 1941; Armstrong, J. E., and Tipper, H. W.,
“ Glaciation in North Central British Columbia,” .4m. 1our. .Sci,, Vol. 246, 1948,
pp. 283-309; Fastad, L., and Laird, D., Soil Survey Report No. 4, Canada Dept.
oj &ricuhre, 1954.1
[Photographs: B.C. 520:92; B.C. 761:36; B.C. 763:38, 48; B.C. 765:107;
B.C. 921:104.1
Nechako Plateau
The Nechako Plateau (see Plate XXIVB) is the northernmost of the three
plateau subdivisions of the Interior Plateau, It is an area of low relief, with great
expanses of flat or gently rolling cowmy, in places almost completely undissected
but elsewhere incised to the level of the Fraser River and its tributaries. The plateau
surface lies between 4,000 and 5,000 feet elevation.
The Nechako Plateau is bounded on the west by the Hazelton Mountains and
cm the north by the Skeena and Omineca Mountains. The plateau passes by rapid
transition into the mountains> and the boundaT is drawn along the generalized line
of the 5,000-foot conmur. On the east it is bounded by the Fraser Basin, the line
of separation between the two being the 3,000.foot contour. On the south the separation
from the Fraser Pla&w is along the West Road River.
Over much of the plateau, flat or gentIy dipping Tertiary lava flows cover, the
older volcanic and sedimentary rocks of the Takla and Hazelton Groups and introsive
rocks of Upper Jurassic and Cretaceous age. Glacial drift is widespread and a
high percentage of bedrock is obscured.
The plateau was occupied by ice, which, in moving across it, marked the swface
with thousands of grooves and drumlin-like ridges which are parallel to the ice
flow. From the general vicinity of Ootsa Lake the ice moved eastward and northeastward
toward the Rocky Mountains near McLeod Lake. Ice moved swtheastward
along the Babine Lake valley and then veered to the northeast (ax Fig. 10).
Numerous depressions left on the plateau surface after the ice r&eat are now occupied
by myriads of lakes, from small ponds to lakes the size of Babine, which is the
second largest lake in the Province.
Noticeable features of the pktteau surface are eskers and m&v&r channels;
many of the latter arc now dry. These features are observed only on aerial photographs
or on the ground, because the 500.foot contour interval on the available
mpographic maps is too large to dtsplay features of such low relief.
In the southwestern part of the Nechako Plateau, between Whitesail Lake and
the West Road River, several round-topped ranges project above the general upland
surface at 5,000 feet. An elevation of 7,396 feet is reached at Michel Peak in the
Qmmchus Range, of 6,319 feet on Fawnie Nose in the Fawnie Range, and of 7,065
68