30. 



BAJA CALIFORNIA 

 AND SONORA SYSTEMS 



BAJA CALIFORNIA 



Topography 



Baja California is as long as California but only a third as wide. See 

 maps of Figs. 28.1 and 30.1. Its northern half is mountainous with peaks 

 that rise to elevations of over 10,000 feet. These comprise the Peninsular 

 Range, which is a continuation of the ranges of southern California west 

 of the Salton basin. Most of the high area is granite and metamorphosed 

 rocks of the Nevadan type. The southern half of the peninsula is lower in 

 relief and for the most part is a great area of conglomerates, sandstones, 

 agglomerates, and lava flows of post-early or middle Miocene age. See 



Fig. 30.1. Geologic and tec- 

 tonic map of Baja California 

 and the Gulf of California, after 

 Beal, 1948. Grm, crystalline 

 rocks of Nevadan complex; Km, 

 Lower Cretaceous San Fernando 

 formation; Kr, Upper Cretaceous 

 Rosaria formation; Tt, Paleocene 

 or Eocene Tapetate formation; 

 Tm, Oliogocene to Pliocene for- 

 mations. 



480 



