GEOLOGY OF BAJA CALIFORNIA. 173 



V 



NOTES ON THE GEOLOGY OF BAJA CALIFORNIA, MEXICO. 



BY W. LINDGREN, U. S. GEOL. SURVEY. 



[The notes here presented are based on observations taken during a few 

 weeks' visit in January, 1888, to the vicioity of Todos Sautos Bay and the 

 mountains east of it. They are necessarily somewhat fragmentary, espe- 

 cially as inclement rainy weather and snow in the mountains greatly inter- 

 fered with the work. This paper will shortly be followed by another devoted 

 to the micropetrography of the region here described.] 



But little is at present known of the geology of the Cali- 

 fornian Peninsiila or Baja California. Almost the only 

 trustworthy source is Prof. Gabb's description, published 

 in the Appendix to Whitney's "Geology of California," Vol. 

 I. This paper is founded on observations during a trip 

 through the entire peninsula from La Paz to San Diego, 

 undertaken in 1867, with Mr. J. Ross Browne, Sr., in order 

 to examine certain land grants in the central part of the 

 territory. 



Some notes relating to the peninsula are found in the re- 

 ports of the Mexican Boundary Survey and in Prof. Blake's 

 geological notes accompanying the Pacific Railroad Reports. 

 The only paper relating to the palaeontology of the territo- 

 ry is Dr. C. A. White's " On New Cretaceous Fossils from 

 California," Bull. No. 22, U. S. Geol. Survey publications. 



GENERAL TOPOGRAPHY. 



The peninsula of Lower or Baja California is nearly 700 

 miles long, and on an average 60 miles wide; it extends 

 from lat. 23° to 32° 30'. Generally speaking, it is occupied 

 by a "one-sided" mountain range, sloping gradually and 

 gently towards the Pacific, abruptly towards the Gulf of 

 California, or, in the north, to the low deserts adjoining the 

 gulf. Following Prof. Gabb, we may, topographically, 

 divide the territory into three parts : 



2d Ser. Vol. I. Issued September 25, 1888. 



