PHYSIOGRAPHY OF KLAMATH MOUNTAINS 147 
that these ranges represent axes of structural development that 
are very old compared to others that may be described. 
Notwithstanding the fact that they have an east and west 
course, that has had a controlling influence upon the greater 
drainage, still it is not difficult to also recognize the north and 
south lines of folding traversing the country. South and west 
of the Trinity River the northwesterly direction of folding is 
shown by the course of all the larger streams. But even in the 
more central and most confused section of the Klamath group, 
that lying between the drainage basins of Rogue River and the 
Trinity, the north and south trend of the ranges impresses itself 
upon an observer, and the crossing of the ranges forms a mag- 
nificent spectacle for one who appreciates the larger features of 
mountain topography—and the influence of the factors controll- 
ing them is carried even into the smaller structural details of the 
country, regulating even the course of many smaller streams as 
well as that of dikes and auriferous veins. 
Evidences of a peneplain.— Possibly to these facts is due ina 
measure the appearance in many portions of the group of a great 
uplift and dissected plain. Standing on any of the higher eleva- 
tions of the country, say at an altitude of about five thousand 
feet, and looking over the surrounding mountains, one is often 
struck by the comparative uniformity of their outlines against 
the sky. From four to five thousand feet is for the most part 
their greatest altitude, and there are long ranges and ridges that 
stretch for miles at nearly a uniform level within these limits. 
One of the best examples of this fact is the South Fork range 
on the western boundary of Trinity county, which makes an even 
sky line for forty miles or more at an altitude above five thou- 
sand feet. The Siskiyous, the Yallo Bally, and Bally Choop 
ranges all furnish good examples of the same character. The 
general effect of this uniformity of level is that already sug- 
gested as a great uplifted and dissected peneplain that has been 
warped and diversified by differential movements subsequent to 
its development. South of the latitude of Cape Mendicino, Dr. 
Lawson has stated,’ there is a broad peneplain that rises from a 
* Bull, Geol. Depart. Univ. Cal., Vol. I, pp. 242-44. 
