72 H. W. FAIRBANKS — GEOLOGY OF THE COAST RANGES. 



Page 



Metamorphism incident to the movement 91 



Dynamic metamorphism ... 91 



Chemical metamorphism 91 



Correlation of the quartz- veins 92 



Age of the sedimentary series 93 



Paleontologic evidence 93 



Stratigraphic and mhologic evidence 94 



Cretaceous of the Coast ranges 95 



Distribution 95 



Separation from the pre-Cretaceous by an unconformity 96 



Absence of regional metamorphism 96 



Lithologic character 96 



Eelation of the Chico to Lower Cretaceous and pre-Cretaceous 97 



Probable epoch of the serpentine intrusion and its effect upon the Cre- 

 taceous 98 



Tertiary of the Coast ranges 99 



Eocene 99 



Miocene 99 



Formation of new axes with each succeeding elevation 100 



The Coast ranges constitute a mountain system 101 



Sketch of the geologic history of the Coast ranges 101 



Conclusions 102 



Scope of the Paper. 



In the follov^ing article it is intended to set forth, so far as is possible 

 with the information at hand, the present state of our knowledge of the 

 geology of the Coast ranges of California. The central theme in the pre- 

 sentation will be a discussion of the evidence supporting the view of the 

 pre-Cretaceous age of the uncrystalline basement rocks of this region. 

 The evidence treated of will deal partly with some results of recent field- 

 work in the southern portion of the area and partly with a more detailed 

 restatement of the conditions found to obtain in northern California. A 

 brief summary will also be made of the characters of the oldest rocks in 

 the Coast ranges — the granites, crystalline schists and limestones — as well 

 as of the Cretaceous and Tertiary formations, and of the disturbances 

 which have taken place, as indicated by the relation of these formations 

 to each other. 



It is with no intention of putting forth categorical statements concern- 

 ing disputed questions that this article is prepared, but of giving more 

 definite and explicit reasons for some previous views published by the 

 writer in the American Geologist.* Many of the opinions therein ex- 



* American Geologist, vol. ix, 1892, pp. 153-156, and vol. xi, 1893, pp. 70-84. 



