Landforms of British Columbia 1976 - Department of Geography

(3) Hypsometric lines (that is, lines of equal elevation or a line that approxi-
mates the position of the contour line), such as the 2,000-foot contour
limiting the Fort Nelson Plain, the 3,000-foot contour outlining the Liard
Plain and Fraser Basin, and the 5,000-foot contour marking the upper
limit of the Nechako Plateau. In some instances, lines of types ( 1) or
(3) may coincide with structural lines.
(4) Geological contacts, such as the contact of the Upper Cretaceo’us sedi-
mentary rocks in the Suquash and Alberni Basins, and the eastern edge
of the Misinchinka schists in the Misinchinka Ranges.
ILLUSTRATIONS
The text very largely describes the boundaries of the various units and indi-
cates something of their physiographic history, but the photographic illustrations in
this report are perhaps equally important. The accompanying map, Figure 1, is
a special edition of the Department of Lands, Forests, and Water Resources Map
~JP. It shows the physiographic subdivisions of the Province in which the land-
forms in general appearance and origin are essentially alike.
The outlines of the physiographic subdivisions were transcribed from bound-
aries located on National Topographic System Map sheets at 4 miles to the inch
and with 500-foot contours. Anyone wishing specific topographic information
should obtain these more detailed maps either from the Map Distribution Office,
Department of Mines and Technical Surveys, Ottawa, or from the Chief Geographer,
Department of Lands, Forests, and Water Resources, Victoria.
The photographic illustrations convey a far better picture of the character of
the terrain than could be done by words alone. The position and line of sight of
each is shown by numbered arrows on Figure 9,
The photographic illustrations are prepared from oblique aerial photographs
taken from aircraft flying at altitudes of 16,000 to 18,000 feet. The photographs
are very largely those taken by the Air Survey Division of the Department of Lands,
Forests, and Water Resources, Victoria. Copies of these photographs or the ones
listed under “ References ” may be ordered from the Air Photo Library, Depart-
ment of Lands, Forests, and Water Resources, Victoria. Some are reproduced
through courtesy of the Royal Canadian Air Force, copies of which may be obtained
from the National Air Photo Library, Department of Mines and Technical Surveys,
Ottawa. The photographs are selected to illustrate characteristic features of the
landscape in all parts of the Province.
Those who wish additional oblique aerial photographs of areas not illustrated
here may obtain index maps from the Air Photo Library, Department of Lands,
Forests, and Water Resources, Victoria, which show the flight lines and picture
nmbers for ordering. A very large part of the Province is covered by oblique
photography, and where these pictures are available, they, together with topographic
maps, provide an extremely valuable source of information for detailed physio-
graphic studies. Nevertheless, in some areas oblique photographic coverage is poor
or lacking. These are the Selkirk and Purcell Mountains, Rocky Mountains and
Foothills north of Golden, Omineca and Cassiar Mountains, and Queen Charlotte
Islands.
The geological diagrams, Figures 2 to 7, are adapted from the geological map
published in the British Columbia Atlas of Resources, B.C. Natural Resources
Conference, 1956.
The glacial diagram, Figure 10, is adapted from the map of glacial geology in
the same atlas.
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