UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



No. 3, pp. 39-87, Pis. 6-7 ANDREW C. LAWSC 



A GEOLOGICAL SECTION 



OF THE 



COAST RANGES NORTH OF THE 

 BAY OF SAN FRANCISCO. 



BY 



Vance 0. Osmont. 



CONTENTS. 



PAGE 



Introduction 41 



Pre-Francisean 42 



Sedimentaries 41! 



Bodega Diorite 43 



Field Aspects 43 



Petrography 44 



Biotite-Diorite 44 



Quartz- Biotite-Diorite 45 



Chemical Analyses 46 



Basic Secretions 47 



Acid Dykes 47 



Correlation and Age 48 



Franciscan 48 



Constituent Formations 48 



Areal Distribution 49 



Quicksilver Deposits 50 



Shasta-Chico 51 



Lithologieal Character 51 



Stratigraphy 51 



Tejon 53 



Yellow Sandstones on Carneros Creek 53 



Monterey 53 



Point Reyes Peninsula 53 



San Pablo 54 



Blue Sandstone (tuff) of Carneros Creek 54 



