Landforms of British Columbia 1976 - Department of Geography

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The range is composed of folded sedimentary and volcanic rocks of Triassic
and Lower Cretaceous age that are intruded at Hazelton Peak by a small granitic
stock.
The peaks are serrate in profile and show the effects of late-stage cirque glacia-
tion. On the eastern and southern sides of the mountain mass the slopes are strongly
glaciated by ice that flowed down the valleys of the Kispiox and Skeena Rivers.
[Reference: Armstrong, J. E., “ Preliminary Map,, Hazelton Area,” Ge& %uv.,
Canada, Paper 44-24.1
Bulkley Ranges
The Bulkley Ranges lie east of the eastern contact of the Coast Intrusions, south
of the Skeena River, and west of the Bulkley River. South of Telkwa the ranges pass
by transition into the Nechako Plateau along a generalized line about at the 5,000-
foot contour.
The ranges include the Seven Sisters group of peaks (maximum elevation 9,140
feet), Rocher Deboule Range (Brian Boru Peak 8,200 feet), Hudson Bay Moun-
tain (8,400 feet), Telkwa Range (maximum elevation 7,672 feet), Howson Range
with peaks to 8,500 feet, and other unnamed ranges. Most of these ranges and
mountain groups have central stocks of granite. The high peaks are sculptured by
cirques and glaciers, some of which still cling to peaks in the Howson Range, the
Seven Sisters, and other peaks near the Skeena River.
Back from the Skeena River the individual ranges are bounded by wide flaring
valleys such as those of the Zymoetz and Telkwa Rivers, flowing at elevations be-
tween 2,000 and 2,500 feet. These wide valleys become more prominent in the
eastern part of the Bulkley Ranges and are noticeably different from the narrow,
deep glaciated valleys of the Kitimat Ranges on the west.
In the Pleistocene, ice covered the area to an elevation of 6,000 to 7,000 feet.
An ice divide near Smithers separated ice which moved down the Bulkley and Skeena
Valleys to Terrace and thence down the Kitimat Valley to the sea, from ice which
moved southeastward up the Bulkley River valley onto the Nechako Plateau and
thence eastward toward the Rocky Mountains (see Fig. 10).
[References: Kindle, E. D., “ Mineral Resources, Hazelton and Smithers
Areas,” Geol. Surv., Canada, Mem. 223, 1940; Sutherland Brown, A., “ Geology
of the Rocher Deboule Range,” B.C. Dept. of Mines, Bull. No. 43, 1960.1
[Photographs: B.C. 468:39; B.C. 505:65; B.C. 522:114; B.C. 523:97; B.C.
525:9, 18.1
Tahtsa Ranges
The Tahtsa Ranges (see Plate XXIB) lie east of the eastern contact of the
Coast Intrusions, flanking the Kitimat Ranges from Morice Lake southward for about
40 miles to the west end of Eutsuk Lake. The ranges represent a belt 10 to 15 miles
wide of essentially non-granitic mountains between the Nechako Plateau on the east
and the dominantly granitic Kitimat Ranges on the west.
The highest point in the ranges is a peak of 8,103 feet east of Nanika Lake.
The rest of the high peaks generally range between 7,000 and 7,500 feet. The peaks
and ridges are serrate and exhibit the sculptural effects of cirque glaciation; many
of the highest peaks still carry cirque glaciers on their northeast sides.
The mountains are divided into westerly trending ranges. They lie between
major valleys that are occupied by lakes which, from north to south, are Morice,
Nanika, Tahtsa, Troitsa, Whitesail, and Eutsuk. These lakes are between 2,614
and 3,100 feet in elevation and drain eastward into tributaries of the Fraser River.
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