t907.] 



CRANDALL— SAN FRANCISCO PENINSULA. 



35 



lower than their original one, and there has been an apparent devel- 

 opment of a minor syncline on the south side of San Andreas Lake 

 parallel to the fault line in places, while the Franciscan beds on the 

 north side of the lake dip sharply to the southwest. The total 

 throw of this fault is indicated by the amount that Franciscan 

 beds on the northeast side of the fault are lower than those of the 

 same horizon on the southwest side, and that is about 500 feet. 



Fig. 13. 



The San Bruno anticline exposed in the cliffs one mile north of Point 



San Bruno. 



This displacement has been spoken of here as a single movement, 

 but it must be taken as the algebraic sum of all the movements 

 up to the present time rather than as a single movement. That the 

 upthrow of this fault is on the northeast side is confirmed by the 

 evidence in the Santa Cruz quadrangle where the Franciscan beds 

 in Black Mountain are higher than the Miocene beds southwest of 

 the fault. 



Minor Faults. — Of the minor faults there are only two worthy 

 of consideration ; these are the Visitation Valley and the Wood's 

 Gulch faults. 



Visitation Valley Fault. — There are likewise two minor faults 

 parallel to these main fault lines and possibly a third one. The 



