112 SOUTHERN CALIFORNIA GEOLOGY 



MASTER FAULTS 



The master faults are faults of great displace- 

 ment which persist throughout long distances and 

 more or less coincide with the broad features of the 

 topography. Master faults, like the great Balcones 

 fault of Texas, the Grand Wash Cliffs of Arizona, the 

 Wasatch fault of Utah and the Sierra Nevada faults of 

 California, constitute conspicuous lineaments of the 

 physiography and may outline geographic units of large 

 size. They are often traceable throughout long dis- 

 tances from tens to hundreds of miles. In Southern 

 California they are usually associated with one or 

 more of the borders of the greater physiographic units 

 and usually mark the boundary lines between the mas- 

 ter highlands and the larger valley plains. They have 

 vertical displacements of as much as 15,000 feet. 



In this category of major faults we place, among 

 others the Newberry, Cadiz, Pinto Mountain, San An- 

 dreas, Mill Creek, San Jacinto, Elsinore, Puente, Ana- 

 capa, Santa Ynez, Bouquet Canyon, San Gabriel, Sierra 

 Madre, Santa Monica, Cucamonga and other fault lines, 

 as indicated upon the accompanying map (Plate 11). 

 They are more fully described in other parts of this 

 report. 



These phenomena collectively constitute geologic and 

 physiographic features of extraordinary and stupen- 

 dous interest and are fundamentally and predominantly 

 the chief factors in giving the present day individuality 

 to the scenic aspects of Southern California. After the 

 reader gets a first grasp, even in an elementary way, of 

 their locations and extent, as herein presented upon 

 the accompanying plate (Plate II), they will gradually 

 grow in importance as he learns to recognize them in 



