PHYSIOGRAPHY OF THE BEAVERDELL MAP-AREA. 
29 
occupies such a flume-like valley, and so do the last 5 miles of 
Beaver creek, and the lower ends of Trapper and Wilkinson 
creeks. The characteristic shape of these valleys is especially 
well brought out where side streams are small and scarce, as in 
the lower stretches of the Beaver. The planate sides are steep, 
and since the larger valleys are of this type, their valley walls 
together with the walls of certain of the deeper canyons are the 
most conspicuous feature in the relief of the region. 
The canyon type is exemplified by the canyon occupied 
by Cedar and Larsen creeks, steep sides running down to a 
narrow bottom. Canyons are found at the lower ends of almost 
all the smaller streams draining from the upland into the larger 
valleys of the West Fork and Beaver creeks. Upland draws 
have gently sloping hillsides and rounded rather than fiat bot- 
toms. Such is the valley of Beaver creek between Joan and 
Clark lakes (Figure 2, profile 1) and the draw crossing King 
Solomon mountain on its southeastern end (Figure 2, profile 4). 
An examination of the side hill slopes of valleys of the U and 
canyon types shows that there is an abrupt change in practi- 
cally all cases, somewhere upon the hillside, from the steep 
grades peculiar to these types below to a gentle slope which 
is more nearly that of the upland draw (Figure 2, profiles 1,2, 
and 4). Upon climbing out of the West Fork valley for in- 
stance, one ascends a slope of from 1,800 to 2,500 feet to the mile 
for an elevation varying from 800 to 1,500 feet, according to the 
locality, and then suddenly the grade flattens so that one ap- 
pears to be upon a flat topped hill. As a matter of fact, however, 
there is generally an upward slope of 600 feet to the mile or less 
to the ridge top which may be a mile or more away. As one 
ascends a side stream the gentle slopes descend farther toward 
the valley bottom and the canyon becomes shallower until it 
becomes a narrow trench within a wide upianddraw. Canon 
Creek valley is an example of such a change from canyon to 
broad draw. 
Stream Grades . 
Stream grades along the U-shaped valley bottoms are 
usually quite low. The West Fork averages about 30 feet to 
