Landforms of British Columbia 1976 - Department of Geography

feet), Mount Lloyd George (9:570 feet), Mount Stalin (9,500 feet), and the
highest, Mount Churchill (10,500 feet), at the head of Churchill River and 40
miles south of the Alaska Highway at the Toad River. From Mount St. George
(8,500 feet) just south of the Alaska Highway, the summit Ievel decreases north-
ward to below 7,000 feet in the Terminal Range south of the Liard River.
Eventually the northern Rocky Mountains merge in the Rabbit Plateau in the
northwest and terminate at the Liard River (see Plate XXXVIIA) against the
Liard Plateau, both of which lie for the most part below 5,000 feet elevation.
The mountains are crossed by the Liard and Peace Rivers (see Plate XLIVA),
which are long-established routes of travel, and by the Alaska Highway, which
folhws the Tetsa, MacDonald, Toad, and Trout River valleys. Access from
these routes has provided a framework of geological information. Elsewhere in
the Muskwa Ranges, although topographic maps are available, geological and
structural information is generally unavailable. As a consequence, too little is
known to enable a rigid structural subdivision to he made.
A beIt of Misinchinka schists extends along the western side of the Muskwa
Ranges for 120 miles northwestward from the Peace River to the mouth of the
Kwadacha River near Fort Ware. This belt of schist is about 5 miles wide and is
the extension north of the Peace River of the Misinchinka Ranges. Streams crossing
the belt enter the Trench along a south 35 degrees west direction. ‘I?x high point
along the belt is Deserters Peak (7,430 feet), just east of Deserters Canyon on the
Finlay River. Summit heights underlain by these rocks are lower than those in the
bolder limestone and quart&e ranges to the east.
On their eastern side the Mwkwa Ranges are eroded largely in Devonian and
Permo-Carboniferous limestones. They are bold caste&ted ranges of considerable
relief which, in the vicinity of the headwaters of the Prophet and Muskwa Rivers,
appear to have undergone a minimum of late-stage alpine and cirqne glaciation.
A distinctive physiographic unit within the northern ranges extends for an
unknown distance southward from the Alaska Highway at MiIe 432, The area is
underlain largely by a succession of quart&es, conglomerates, slates, and phyllitic
limestones (Kechika Formation) which are late Precambrian and Cambrian in age.
These rocks underlie an area which, between the head of Toad River and the
Tetsa River, is 30 miles wide but which may expand to a width of SO miles between
the Tuchodi Lakes and Mount Lloyd George. It includes the high peaks of
Mount Churchill (10,500 feet), Mount Roosevelt (9,500 feet), and Mount Stalin
(9,500 feet), and extends southward at least to Mount Lloyd George (9,570 feet)
and surrounding high peaks. Quart&es in the succession underlie many of the
high peaks of a region that is very little known. Comparable rocks (Kechika and
pre-Kechika Formations) are exposed west of Muncho Lake and Trout River in
the core of the Terminal Range, which is a northwesterly plunging anticlinorium.
The high area south of the Alaska Highway has been strongly eroded by alpine
and valley glaciers, and it is evident from topographic maps that the valleys of
Gataga River, Toad River-Munch0 Lake, Racing, Muskwa, and Kwadacha Rivers
served as escape routes for ice which accumulated in the high area centring around
Mounts Lloyd George, Churchill, Roosevelt, and Stalin, The high aey quart&e
and limestone mountains of great relief with glacially sculptured cirques and alpine
valleys present scenery comparable to that in the Park (Main) Ranges of the
southern Rocky Mountains.
The Alaska Highway, between the eastern front of the Rocky Mountains at
MiIe 389 and the Muncho Lake valley, crosses two ranges which consist of fault
blocks lying above westerly dipping thrust faults. These ranges are physiographically
and structurally similar to the Park Ranges and are formed from thick Sihtrian and
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