THE PHYSIOGRAPHIC BEATURES OF DHE KIA MAGE 
MOUNTAINS. 
CONTENTS. 
Introduction. Neocene deposits. 
General features. Lake systems of the Neocene. 
The chief ranges. Volcanic activity. 
Evidences of a peneplain. The Cascade range. 
Valley depressions. Lavas of the region. 
Type of valleys. The Tuscan tuff. 
Deductions. Faulting of the region. 
The larger basins. Development of the present drainage. 
The later sedimentary deposits. Summary and conclusions. 
The Chico deposits. 
INTRODUCTION. 
Tue Klamath Mountains were frst recognized as a group 
deserving to be distinguished from other Coast Ranges and the 
Sierra Nevada when C. E. Dutton and J. S. Diller began their 
reconnaissance work in northern California and southern Oregon. 
It was first outlined in 1886 by Captain Dutton’ as including all - 
the mountains lying to the west of the upper Sacramento and 
Rogue River valleys, and probably other mountains of a similar 
age joining them on the north and south. The group was more 
definitely defined and characterized by Mr. Diller in 1892-93,? 
and their limits were extended southward beyond the fortieth 
parallel and northward to include the Rogue River Mountains, 
and some of the mountains of the upper Umpqua basin. Accord- 
ing to Mr. Diller the name was first proposed by Major Powell 
many years earlier. 
Geologically, the group of ranges now known as the Klamath 
Mountains resembles the Sierra Nevada in age and in the char- 
acter of their formations, both igneous and sedimentary, though 
but little has yet been done to show their geological features, 
* Seventh Ann. Rept. U. S. Geol. Surv., pp. 97-103. 
2 Fourteenth Ann. Rept. U. S. Geol. Surv., Pt. Il, pp. 403-34. 
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