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



south to the fortieth parallel, the limit of his field, it is the object of the 

 writer to demonstrate can be traced through the Coast ranges as far south 

 as Santa Barbara county. 



Orographic Movement. 

 its extent and time of occurrence. 



The upheaval which caused the deformation and metamorphism of 

 the rocks of the Klamath mountains, there is good evidence to affirm, 

 extended south as far as the rocks under discussion can be traced. The 

 evidence adduced by Mr Goodyear of the gradual decrease of meta- 

 morphism southward should have great weight. His views, as expressed 

 in the coloring of the preliminary geological map published by the Cali- 

 fornia State Mining Bureau, show that he considered the rocks of the 

 Yallo Bally mountains as more metamorphosed portions of the Creta- 

 ceous. In believing them to be Cretaceous he simply followed the pre- 

 vailing views as to the " metamorphic series." In all his references to 

 the slate, §andstone and jasper of the northern Coast ranges he conveys 

 the idea that they all belong to one series. Time and again he also 

 remarks upon the extreme deformation to which they have been sub- 

 jected, as often shown by the complete obliteration of the stratification. 

 This latter feature has been remarked by nearly all the workers in Cali- 

 fornia geology. 



PH YSICA L MA NIFES TA TIONS. 



This remarkable convulsion had the efi'ect of mashing the strata to- 

 gether and forming sharp folds. The character of the deformation is one 

 of the most striking features of the pre-Cretaceous series as a whole, and is 

 one of the many means by which it can very often be distinguished from 

 the overlying Cretaceous. Although in the majority of cases the actual 

 contact of the recognized Cretaceous with the older rocks cannot be found, 

 yet the crushed and broken condition of the latter is in most marked con- 

 trast to the comparatively regular stratification of the Cretaceous, and is 

 good proof of a physical break. The following quotation from Becker * 

 is interesting as bearing on this point, and shows how different were the 

 conditions of mountain-making at the time of this upheaval from those 

 of any subsequent period : 



"The metamorphic rocks have been dislocated in the most violent manner; 

 indeed, the greater part of the mass was crushed at the time of the metamorphism 

 to a small rubble. This is the case throughout the entire quicksilver belt, and 

 renders it utterl_y impossible to plot any sections of the metamorphic strata." 



* Quicksilver Deposits of the Pacific Slope, p. 293. 



