8 
MUSEUM BULLETIN NO. 11. 
maps of three widely separated areas 1 supplemented by descrip- 
tions of the topography by Dawson 2 . The topographic maps 
are those of the Beaverdell area; of the Tulameen area; and 
of the Kamloops and Shuswap areas, whose location is shown in 
Figure 1. 
THE UPLANDS. 
A study of the upland surface was made along the following 
lines: (1) the degree of regional slope and relief upon its surface, 
the variation of such slope in the different areas and the presence 
or absence of a relation between general slope and drainage lines; 
(2) the presence or absence of local irregularities of slope, cliffs, 
flat areas, and steep hillsides differing widely from the general 
slope; (3) the nature of the soil covering; (4) the drainage upon 
the upland and its relation to the drainage along the deep valleys ; 
(5) finally, the presence or absence of a relation between the 
upland surface and the structure of the underlying rocks. The 
data so obtained were used later to determine to what stage the 
upland surface had progressed in its evolution through the 
geographic cycle. 
Regional Slopes. 
The deep valleys divide the upland into broad, rather irregu- 
lar ridges. If one were to project the upland surface across the 
main valleys and imagine the valleys filled up to the base of the 
shallow trough thus formed, the resultant all-upland surface 
would show marked relief. Measurements made upon the three 
topographic maps show that the average regional slopes from the 
^‘Kamloops and Shuswap sheets, British Columbia; Tulameen sheet, 
Yale district, British Columbia; map 36A, Beaverdell, Yale district, British 
Columbia," Geol. Surv., Canada. 
2 “0n the later physiographical geology of the Rocky Mountain region 
in Canada, with special reference to changes in elevation and to the history 
of the Glacial Period," by G. M. Dawson. Trans. Roy. Soc, Can., vol. 8, sec. 
4, 1890, pp. 3-74. 
“Report on the area of the Kamloops map sheet, British Columbia,” 
by George M. Dawson, Geol. Surv., Canada, No. 573, pp. 3B-6B, 1896. 
