192 CALIFORNIA ACADEMY OF SCIENCES [Proc. 3D Ser. 



some of the accessible literature contains only unsatisfactory 

 figures and descriptions; therefore it is highly desirable to 

 have re-descriptions and better drawings made when authen- 

 tic material can be obtained and properly identified. The 

 species figured and described by Conrad in the Pacific Rail- 

 road Reports can rarely be identified except from the type 

 localities, and then only by the utmost care and reservation ; 

 the same is often true of the species described by Gabb in 

 the Paleontology of California. Much of the confusion and 

 uncertainty in stratigraphic determination in the Pacific Coast 

 Tertiary originates in such faulty descriptions. Correct 

 specific determinations cannot be made from much of the 

 literature upon California paleontology that is accessible to 

 students of the subject, and until these can be made, trust- 

 worthy determinations of faunal horizons are likewise impos- 

 sible. 



Where any departure has been made from the current 

 paleontological nomenclature it has been with deference to 

 the classification proposed by Zittel in his Handbuch der 

 Palceontologie, and it must be confessed that such a standard 

 should have been adopted throughout. An attempt to do 

 this would, however, involve a considerable amount of work 

 in revising the Pacific Coast nomenclature, and that is beyond 

 the purpose of this paper. 



The paleontological materials that form the basis of this 

 study have been largely collected by the writer ; they have 

 become the property of the California Academy of Sciences, 

 and are a part of its permanent collections. 



FORAMINIFERA. 



Eocene. 



Plate XIII, Figs. 9-29. 



For the purpose of calling attention to the many well pre- 

 served forms of Foraminifera in the Eocene rocks of the 

 Mount Diablo Range, and to illustrate some of the more 

 common genera, a few have been figured without any attempt 



