Landforms of British Columbia 1976 - Department of Geography

The area is drained by the Finlay, Mesilinka, Ingenika, and Omineca Rivers,
and by tributaries flowing into the head of the Skeena River. Valley bottoms lie
between 3,000 and 4,000 feet, so that the relief, even in the most rugged sections,
is less than it is in the Coast Mountains.
The mountains were glaciated throughout, but with an intensity that varied
with altitude and general location. Mountain peaks and ridges below 6,000 feet
are rounded, but at progressively greater heights the peaks are more serrate and
show the sculptural effects of cirque glaciation. In the ranges near the Finlay River
the valley profiles are U-shaped and hanging valleys are to be seen, but in the
vicinity of the Om%~eca River ice erosion, except for late-stage cirque glaciation,
was far less pronounced, A mantle of drift was left in the valley bottoms, and many
low-level lakes resulted from its irregular distribution. Many derangements of the
pre-glacial stream pattern resulting from the ice occupation are described by Roots*
in the Aiken Lake area.
A few remnants of the late Tertiary erosion surface are to be seen in the
McConnell and Wrede Ranges, but farther east the landscape is completely mature;
the old erosion surface is completely dissected and no remnants of it remain.
The relation between topography aid geology is illustrated by the coincidence
of the highcst peaks and mountain crests with the axis of the batholith. There are,
moreover, close topographic and geologic similarities between the Wolverine, Ten-
akihi,‘Ingenika, Tucha, and Fishing Ranges, all of which lie on the eastern side of
the Omineca Intrusions and are eroded from highly metamorphosed rocks of late
Precambrian and early Palreozoic age.
[References: Lord, C. S., “McConnell Creek Map-area,” GeoI. Surv., Canada,
Man. 251, 1948; Armstrong, J. E., “Fort St. James Map-area,” Geol. Surv.,
Canada, Man. 2S2, 1949; Roots, E. F., “Geology and Mineral Deposits of Aiken
Lake Map-area,” Geol. Surv., Canada, Mem 274, 1954.1
The Finlay Ranges Ye between the Pelly Creek linearneat and the Rocky
Mountain Trench, and extend for 130 miles along the Finlay River northward from
the mouth of the Omineca River to the mouth of Obo Creek. The ranges have a
width of 15 miles.
Peaks ranging from 6,000 feet to just over 7,000 feet are eroded from lime-
stones, quart&es, and highly metamorphosed schists of late Precambrian and
Cambrian age. The structural trend of the rocks controls the northwesterly direction
of the ranges.
The ranges were glaciated, but no i= remains. The peaks and ridges were
rounded during the maximum transgression of the Cordilleran ice-sheet. Later
cirque and valley glaciers left their characteristic imprint upon the topography.
The Finlay Ranges are geologically and structurally continuous with the Sifton
Ranees to the north, from which they are separated along strike by the valley of
the Finlay River.
[References: Dohnage, V., “Finlay River District,” Geol. Surv., Canada,
Sum Rept., 1927, Pt. A; Roots, E. F., “Geology and Mineral Deposits of Aiken
Lake Map-area,” Geol. Swv., Canada, Mem. 274, 1954.1
Hogem Ranges
The Hogem Ranges lie to the west of a line that follows the Pinchi Lake-
Omineca fault and extends north to Thutade Lake, by way of Sustut Lake and
* m.a,s, E. F., Gd. SW”., colmi.7, Me*, 274, ,954, p. 1%
64