22 TOPOGRAPHIC DEVELOPMENT OF KLAMATH MOUNTAINS, [bull. 196. 
of the Klamath Mountains. To the southward the view of the Glenn 
County foothills presents a very smooth, even skyline, gently dipping 
eastward for miles. No one could see this slope and doubt the former 
continuity of the plain marked by the even-crested ridges in the foot- 
hills of Colusa County. 
The eastern slope of the Klamath Mountains is less regular north 
of the fortieth parallel than farther south. The plain is warped and 
broken by displacement and erosion, but near the summit of the 
range the gentler features reappear in the platform of the Yallo Bally 
Mountains, which has a general altitude of about 7,000 feet. 
The only point near the coast in California where the two plains 
have been separated is at the northern end of Bear Ridge, which is 
surmounted by an older plain of gentle relief at an altitude of about 
2,500 feet, while on the north slope at 2,000 feet there is a well-marked 
plain cut upon the upturned edges of the Wildcat series. In Oregon 
north of Rogue River, although traces of the second plain have been 
recognized, they appear near the level of the Klamath plain and are 
scarcely distinguishable. It is possible, perhaps probable, that in 
some cases the lower plain is the same as the upper, the discordance 
in the elevations being due to faulting. 
On the eastern side of the range is a peneplain below the Klamath 
peneplain, occupying about the same relative position as the Sher- 
wood plain on the west slope. This plain stretches westward from 
the Bald Hills of Shasta County and its occurrence has been already 
described and illustrated. 1 
THE SHERWOOD PENEPLAIN. 
In the foregoing part of this paper the plateau-making peneplains 
have been regarded as the Klamath and the Bellspring, although lower 
peneplains were mentioned as occurring at a number of places. The 
lower plain is most extensively developed along the South Fork of Eel 
River and about Sherwood, near the center of Mendocino County, at 
an elevation ranging from 2,400 to 2,800 feet on the divide between 
the head of the South Fork and Eel River and the main stream to 
the east. In Cahto Peak, about 20 miles northwest of Sherwood, the 
older peneplain is preserved at about 4,200 feet — that is, at least 1,400 
feet above the Sherwood plain. The general views of the Sherwood 
plain were not so clear and extensive as was desired, but it appears 
to stretch far eastward and northeastward toward the crest of the 
range, possibly connecting with the one which occurs in Hay Fork Gap 
at 5,000 feet. It is much lower than the southeastern end of South 
Fork Mountain, which carries upon its even crest the Klamath pene- 
plain at an altitude of over 6,000 feet. There thus seems to be an 
increasing difference in the altitude of the two plains toward the crest 
of the range. 
1 Fourteenth Ann. Rept. U. S. Geol. Survey, Part II, 1894, pp. 406, 410, 412. 
