Landforms of British Columbia 1976 - Department of Geography
Landforms of British Columbia 1976 - Department of Geography
Landforms of British Columbia 1976 - Department of Geography
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high total relief and the massive boldness <strong>of</strong> the mountains provide some striking<br />
mountain scenery. Strongly glaciated valleys which were subsequenly blocked by<br />
glacial debris contain the basins <strong>of</strong> Bowon, Isaac, Lanezi, Hobson, Quesnel, Azure,<br />
and Clearwater Lakes.<br />
The Cariboo Mountains arc composed <strong>of</strong> sedimentary rocks and metamorphased<br />
sedimentary rocks <strong>of</strong> Proterozoic and Lower Cambrian age. Although some<br />
limestone is present, the principal rock type is quart&e in members <strong>of</strong> great thickness.<br />
The rocks are folded about northwesterly striking axes into overturned folds<br />
which in tom may be faulted parallel to their strike. The resistant quart&es to a<br />
large degree influence the topographic forms developed. In the Clearwater area<br />
“the character and structure <strong>of</strong> the underlying formations have noticeably affected<br />
the configuration <strong>of</strong> the present surface. On the upland surface where underlain<br />
by the metamorphic series the peaks arc sharp and the ridges continuous, where<br />
underlaG” by granite the peaks are more massive and rounded and the ridges irregula<br />
or radiating from a central mass.“*<br />
The Cariboo Mountains comprise a number <strong>of</strong> longitudinal ranges trending<br />
northwestward parallel to the strike <strong>of</strong> the underlying sedimentary rocks. Individual<br />
mountains and mountain ranges rise to high serrate peaks <strong>of</strong> heights to<br />
11,750 feet that are glacially sculptured and are separated by steep-walled glaciated<br />
valleys that commonly form a trellis pattern controlled by the underlying bedrock.<br />
The axis <strong>of</strong> the mountains lies to the east <strong>of</strong> Isaac Lake and mns southeastward<br />
through the Premier Group.<br />
The mountains were intensely glaciated, and peaks higher than 8,000 feet<br />
projected through the Pleistocene ice-cap as nunataks which were subjected to<br />
intense frost act:on and cirqw attack. There are some rounded summits and ridges<br />
below 7.000 and 7,500 feet, but intense late-stag? cirqw glaciation on the northern<br />
and northeastern slopes has produced many sharp peaks and sawtooth ridges which<br />
characteristically combine gentler southerly and southwesterly slopes with steep<br />
and abrupt northerly and northeasterly slopes. The intenselv ~- &xi&d trunk vallevs ,~<br />
exhibit G-shaped pi<strong>of</strong>iles, while trib&ary valleys are hanging in relation to them<br />
(a%? Plate xxvIIIc).<br />
[Reference: Sutherland Brown, A,, “Geology <strong>of</strong> the Cariboo River Area,”<br />
B.C. Dept. <strong>of</strong> ,%4&w, Bull. No. 47, 1963.1<br />
[Photographs: B.C. 387:65; B.C. 482:59; B.C. 487:62, 86; B.C. 765:<br />
37, 58.1<br />
The Monashee Mountains (see Plate XXIXA) occupy a northerly trending xca<br />
250 miles long and for the most part 25 to 30 miles wide, lying between the Selkirk<br />
Mountains on the east and the Cariboq Mountains and the Shuswap and Okanagan<br />
HiGhlands on the west. The Monashee Mountains are widest at their southern end<br />
between the Kettle and <strong>Columbia</strong> Rivers, a width <strong>of</strong> 55 miles. The boundaT with<br />
the Selkirk Mountains, southward from Boat Encampment, is along the Colombia<br />
River-Arrow Lakes valley.<br />
The mountains comprise a number <strong>of</strong> individual ranges which have a northerly<br />
to northeasterly trend south <strong>of</strong> latitude 50 degrees 30 minutes, but which swing to<br />
a northwesterly trend farther north. This northwesterly trend is parallel to the<br />
bounding <strong>Columbia</strong> River as far north as Goldstream North <strong>of</strong> Goldstream the<br />
boundaries <strong>of</strong> the Monashee Mountains-namely, the North Thompson and Al-