20 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



cession of unclassified strata, and its complex history and 

 changing faunas, and it clearly marks an advance in our knowl- 

 edge of both the physical events of the time and of the resulting 

 facts of deposition and organic development. The adding of 

 three or four formational names was only incidental to the 

 study and differentiation of the strata, and it was evolutionary 

 and unavoidable, if any progress was to be made in our ac- 

 quaintance "with the real essentials of the geologic history of 

 that time". An increase in names could only be discouraging 

 to one who does not desire an acquaintance with the essential 

 facts, or who assumes an acquaintance that he does not possess, 

 or by one who is unaware of the value of intensive study. 



Within the limits of California there is much to be done in 

 the way of finding a proper basis of stratigraphic classification 

 of the Miocene, and its faunal changes. The area described in 

 the second part of this paper, like many others that should be 

 better known, has its own contribution to make toward the final 

 result, and will serve to illustrate anew an interesting problem, 

 and to some extent show the complicated nature of the Neocene 

 provinces and their environments, and their phases of deposi- 

 tion. Faunal differences have hitherto been ascribed to pro- 

 gressive time development, and inland districts having faunas 

 somewhat different from those along the present coast have 

 been pointed to in proof of such contention, on the theory of a 

 gradual subsidence and progressive continental transgression. 

 The soundness of this view has still to be proved. 



It has yet to be shown that the so-called Vaguer os beds of 

 the Salinas valley are older in time than the Temblor deposits 

 at the base of the Miocene within the Great Valley. Little or 

 nothing is gained by assuming as settled facts, views that upon 

 last analysis will be shown to be purely speculative. 



During the past several years considerable stratigraphic and 

 areal work has been done in and about the oil and gas districts 

 of central California by the writers of this paper, and by those 

 who have contributed to the information and fossil materials 

 herein represented. This work has extended not only over the 

 proved oil districts of the San Joaquin Valley, or better, the 

 Temblor Basin ; but following the lead of prospective evidences 

 of oil it has extended into neighboring territory and into out- 

 lying districts which have contained only doubtful evidences 



