GEOLOGY OF BAJA CALIFORNIA. 29 



and the beginning of the Sierra the depth is nowhere over 

 100 fathoms. Of the geology of the extreme end of the pen- 

 insula very little is known, but according to the few data 

 available it appears that granite and crystalline schists are 

 the predominating rocks.* It can, of course, not be as- 

 serted that there are schists of the same series, and belong- 

 ing to the same uplift as those of Sta. Margarita, but their 

 occurrence in the line of strike of the latter is certainly 

 suggestive. 



In the southern part of the California peninsula there 

 exists then, as far as our limited knowledge permits us to 

 discern, two orographic lines of great importance: 



1. A comparatively recent, probably post-cretaceous line 

 of dislocation, extending from the vicinity of La Paz for 

 many hundred miles northward along the eastern coast. 

 There is, indeed, little doubt that this is the continuation of 

 the fault Hne which I have described in a previous paper, 

 relating to a section from Todos Santos Bay eastward, 

 and which may be traced up to the line between the 

 United States and Mexico. Very likely this is only a fresh 

 break along an old line of disturbance, for a high range, 

 composed of crystaUine schists and granite continues in 

 the same direction from the peninsula of La Paz south- 

 ward. 



2. A line along which an uplift of much greater age 

 than the first one has taken place, and running near the 

 western shore of the peninsula. It possibly extends as far 

 as 400 miles from Cerros Island to Cape San Lucas. This 

 line is indicated by several shorter ranges, mostly com- 

 posed of crystalHne schists and granite, but although its 

 continuity is thus broken, it seems very probable, indeed, 

 that these different parts are due to the action of one and 

 the same orographic force. Very hkely the range was 



*Prof. Gabb's report, Appendix, I, VoL I, Geology of California. 



