TOPOGRAPHIC DEVELOPMENT OF THE 
KLAMATH MOUNTAINS. 
By Joseph S. Diller. 
INTRODUCTION. 
The observations on which this paper is based were begun in 1889 
during a trip across the Coast Range from the Sacramento Valley to 
the mouth of Eel River in California, 1 and have been continued since 
then at intervals, throughout the limits of the Klamath Mountains, 
from the fortieth parallel in California to the Coquille River in Ore- 
gon. In the summer of 1900 several months were spent along the 
coast from Port Orford in Oregon to Clear Lake in California, and 
thence northward by way of Stony Creek on the eastern slope of 
the Coast Range to Bully Choop. Since then a trip has been made, 
chiefly on horseback, from San Francisco northward through the Coast 
Range, Klamath Mountains, and Cascade Range by way of Round 
Valley, Eel River, and the valley of the Klamath, with numerous 
side excursions from the general route. 
The topographic development of the coastal region of California 
from San Francisco to Humboldt Bay has been graphically described 
in an excellent paper by Prof. A. C. Lawson, 2 whose general conclu- 
sions are in many respects essentially the same as those of this paper, 
which gives them a wider and more detailed application. 
THE KLAMATH MOUNTAINS. 
The Klamath Mountains (PI. I), although a portion of the Coast 
Range lying between the fortieth and forty-third parallels of Califor- 
nia and Oregon, are most conveniently treated as if independent. 
They are composed largely of sedimentary and igneous rocks similar 
to those of the Sierra Nevada, but contain also some of Cretaceous 
age. At the north they are easily separated from the Coast Range 
of Oregon, which begins among the Rogue River Mountains and is 
made up chiefly of Eocene sediments. 
1 Fourteenth Ann. Rept. U. S. Geol. Survey, Part II, 1894, p. 408. 
2 The geomorphogeny of the coast of northern California: Bull. Dept. Geol., Univ. California, 
Vol. I, pp. 241-27^. 
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