114 SO'UTHERN CALIFORNIA GEOLOGY 



merits by these subordinate fault traces. This is not- 

 ably true of the City, Washington, and Repetto Hills 

 in Los Angeles. These subordinate fault lines usually 

 extend in directions which are approximately opposite 

 to those of the master rifts, and in instances may be 

 complimental to them. Many of them have northeast- 

 southwest directions. Some of them are older than the 

 master faults, some are newer. 



RECTILINEAR PLAN OF THE FAULTING 



Most of the master fault lines are characterized by 

 long continuity in comparatively straight lines (recti- 

 linearity) although there are some exceptions to this 

 rule. 



Instances like the tangents of the San Andreas rift 

 are traceable for two hundred miles or more in a single 

 direction, with relatively slight deviation from a 

 straight line. There are many other master faults of 

 similar character, notably the Cadiz, Newberry, Mill 

 Creek, San Jacinto, Elsinore, and San Gabriel faults. 



Sometimes, though seldom, the general direction of 

 these faults may be slightly jogged, offset or inter- 

 rupted by minor cross faults. But their long-contin- 

 ued rectilinearities are conspicuous characteristics 

 which are among the most marked features in the 

 geology and physiography of Southern California. 



There are also some few and exceptional instances 

 of faults of curvilinear directions, as in the case of 

 those which accompany the flexured Ventura Ranges. 



NATURE OF THE FAULT LINES 



The master faults are not necessarily single fault 

 lines, but sometimes consist of several, closely-spaced 

 faults which collectively constitute a narrow zone. 



