60 University of California Publications in Geology [Vol. 7 



Comparison with Section on South Side op Mt. Diablo 

 The comparison of the Neocene beds on the north side of 

 the mountain with those on the south side is very interesting, 

 especially as regards the San Pablo series. The San Pablo on 

 the south side of the mountain has a thickness of about 2500 

 feet as against 600 feet on the north side. The lower beds on 

 the south side are more homogeneous than those on the north side 

 of the mountain. The Monterey on the south side lacks the car- 

 bonaceous shales and sandstones seen near the middle of the 

 series on the north side. 



As a whole, it may be said that the Neocene on the north 

 side of the mountain is characterized in a greater degree by 

 strand conditions than are the deposits on the south side of the 

 mountain. 



Summary 



Some of the more important results obtained in a study of 

 the Kirker Pass section are as follows: (1) The deposits of a 

 large part of the middle and upper Monterey had either a 

 fresh-water or an estuarine origin ; (2) the fauna above and below 

 the estuarine beds of the Monterey series is Lower Neocene in 

 age; (3) a well-marked unconformity exists between the Mon- 

 terey and the San Pablo; (4) the San Pablo is to be classed as 

 a series rather than as a formation; (5) the deposits of the San 

 Pablo at Kirker Pass are distinctly littoral, grading from 

 marine to brackish-water conditions; (6) in the middle of the 

 San Pablo series there are evidences of land conditions as shown 

 by an irregular contact, fossil wood, leaf impressions, and the 

 character of the deposits; (7) the Pinole Tuff lies unconformably 

 on the San Pablo. 



