author's use of term coast ranges. 75 



on, the writer hopes to show tlie futility of attempting to frame a defini. 

 tion Inised on tlie age of the rocks, while it is evident at once that none 

 can he given hased on topography, because of the blending into other 

 ranges at both ends. 



The designation Coast ranges as it is used in the present article will 

 include that series of mountain ranges extending west and northwest 

 along the coast from the San En:iidio region of crystalline rocks to and 

 be^'ond the Oregon line. The San Emidio region, l^-ing in northern 

 Ventura county, is the meeting point of the Sierra Nevada and Peninsula 

 ranges. In regard to the designation of the mountains in the northern 

 part of the state, there seems to be no good reason for restricting the use 

 of the term Coast ranges and substituting for it a local name. The usage 

 of most of the earlier geologists is a good one, including, as they did, 

 under the general term all that series of mountains near the coast, not 

 only through California, but Oregon and ^yashington. TiOcal names are 

 perfectly proper and necessary for indicating particular sections, but 

 because of the fact that there are included within the Coast ranges areas 

 of such greatly different age, but not topographically distinct, no local 

 or even general name can imply a geologic distinction. It would seem 

 that the use of the term Klamath mountains is a convenient one and 

 might well be adopted, but without implying any sharply marked geo- 

 logic or topographic distinction. It would seem also that the use of the 

 term Peninsula range for those mountains collectively which extend 

 south from the San Emidio region into the peninsula of Lower California 

 is a very convenient one. 



South of the Santa Clara valley, in Ventura county, as far as the Santa 

 Ana river, there are several mountain ranges the formation of which is 

 largely Tertiary. These are, as a rule, not distinctly detached from the 

 various mountains comprising the Peninsula range. 



Summary of Previous Work. 



The earliest extensive geologic work in this state was undertaken in 

 connection with the Pacific Railroad Survey — Blake, Marcou, Antisell 

 and Newberry, geologists. Considerable study was given to the Coast 

 ranges, particularh^ south of San Francisco. 



A little later Dr Trask spent a part of two seasons working out the 

 geology of the Coast ranges. 



In 18G0 the Geological Survey of California was organized, and work 

 was carried on intermittently until 1874. The results of the work in the 

 coast region is to be found mainly in the volume devoted to general 

 geology and in the two volumes on paleontology. 



