UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF TltE DEPARTMENT OF 



GEOLOGY 



Vol. 9, No. 2, pp. 9-21 Issued June 30, 1915 



THE OCCURRENCE OF OLIGOCENE IN THE 

 CONTRA COSTA HILLS OF MIDDLE 

 CALIFORNIA 



BY 



BRUCE L. CLARK 



UNIVERSITY OF CALIFORNIA PRESS 

 BERKELEY 



