Nechako River Map-Area

gradually to a rounded summit. The apparent uniformity of summit levels in
this subdivision suggests a dessected erosion surface.

NECHAKO

A HILLS
SsLATT
cre 4

Loke

EUCHINIKO

PLATEAU

1
RANGE /¢

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°20 Tunes -West Road ®-

FRASER PLATEAU

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FIGURE 2, Physiographic subdivisions of the Nechako River map-area

Erosion Surface
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Since Jurassic time, this positive area has been undergoing active erosion.
How many cycles have occurred or the manner of erosion is not known. From
a preliminary study, however, it is obvious that there is at least one erosion
surface in this area—the one characteristic of the Interior Plateau (Bostock, 1957,
p. 288)—at about 2,500 to 3,000 feet elevation. This corresponds to the broad
flat areas in the south and to most of the major valley bottoms. These surfaces
rise gradually to the south and, with several interruptions, merge with the more
striking plateau features of the Chilcotin River country. In Nechako River area
this erosion surface is more dissected than it is farther south.

A second erosion surface may be inferred from the accordance of summit
levels. A great number of hilltops have elevations near 4,500 feet and even

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