Landforms of British Columbia 1976 - Department of Geography

LANDFORMS OF BRITISH COLUMBIA
CHAPTER I.-INTRODUCTION
British Columbia is the westernmost Province of Canada. It lies on the Pacihc
Coast of North America, stretching from the International Boundary at the 49th
parallel to the Yukon Border at the 6Oth, a distance of 790 miles. On the west it
is bounded along half its length by the Pacific Ocean and for the remainder by the
narrow mountainous strip of southeastern Alaska. On the east it is bounded by the
Province of Alberta along a boundary which follows the watershed of the Rocky
Mountains northwestward to the 120th degree of longitude and thence northward
along that meridian to latitude 60 degrees north. The area of the Province is
366,255 square miles, of which 6,976 square miles is covered by lakes. It is second
only to Quebec in size and is 9.5 per cent of the area of Canada.
There is a great variety of topography within thii vast region that extends
through 11 degrees of latitude and that extends across the full width of the Canadian
Cordillera from the Interior Plains to the Pacific Ocean. Although the Province is
largely mountainous, with land rising from sea-level to a maximum elevation of
15,300 feet at the summit of Mount Fairweather, nevertheless there are extensive
plateaus, large plains and basins, and areas of prairie. The contrasts and similarities
that extend over great expanses of country and the nature of the terrain itself deserve
to be far better known. To grasp this information requires that the Province be
subdivided into units which are topographically alike and that the landforms be
described in such a way that their origins are understood.
This bulletin is concerned with the physical features of the Province, such as
plains, plateaus, or mountains, as well as valleys, cirques, or volcanic cones; these
are the landforms which combine to make the topography of the Province. Their
description, classification, correlation, and origin comprise the study of geomor-
phology,* which is a branch of the broad field of geology as well as that of physi-
ography. Essentially therefore what follows in this bulletin is the geomorphology
of British Columbia.
A geologic time scale and a glossary of terms are included in an appendix for
the convenience of non-technical readers.
DEVELOPMENT OF LANDFORMS
The topography of British Columbia is constantly changing as the various
features of the landscape are attacked by erosion. The landforms seen today rep-
resent only a stage in a continuously repeated cycle of events during which the land
surface is lowered and destroyed only to be re-elevated or rebuilt at some later time.
A study of landforms makes it possible for the observant eye to piece together
much of the recent history of the earth by disclosure of erosional effects and major
crustal movements. By so doing the course of future modifications may be pre-
dicted. Landscapes provide a record of the earth’s history that is important to a
geologist or geomorphologist, but the same record may be read by an observant
l The term “ physiography ” was formerly used in this sense, but now it is generally used with a wider
meaning to embrace geomorphology, climatology, and oceanography. The word “ physiographic ” is well estab-
lished in such uses as “ physiographic subdivision ” or “ physiographic history,” which refer only to landforms,
and is used here in preference to “ geomorphologic,” which is synonymous but cumbersome.
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