THE GEOLOGY OF THE SAN FRANCISCO PENINSULA.^ 



(with a map.) 



By Roderic Crandall. 

 {Read January 4, 190/.) 



Introduction. 



The main points to be covered in this paper will be stated in 

 the beginning. These are : 



1. A description of the terranes mapped with an outline of the 

 petrography of each. 



2. A description of the structure of the area with the resulting 

 physiography. 



3. A general discussion of five points of special interest : The 

 age of the non-crystalline sedimentary rocks of the Franciscan 

 or Golden Gate series ; the origin of the IMerced series ; the origin 

 of the jaspers, serpentines and metamorphic schists. In the general 

 discussion it will be realized that this is the application of informa- 

 tion from work done by others to local problems, in an endeaveor 

 to throw any light possible upon some of the complex problems of 

 the Coast Range geology. 



The actual field work has been much facilitated by the good 

 maps available. On the whole area the map of the U. S. Geological 

 Survey has been found excellent, the topography of this map being 

 mostly the work of the U. S. Coast and Geodetic Survey. In the 

 city proper the map of Britton & Rey was found very good for 

 street location. The photographs with the exception of three, two 

 of the anticline near San Bruno point and one of the relief map of 

 San Francisco, are the work of Mr. Robert jMoran. The three ex- 

 cepted were taken by ]Mr. Berton Crandall. 



^ A thesis for the degree of A.M., presented to the Department of Geol- 

 ogy of Stanford University, April, 1907. 



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