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



heavy beds of conglomerate in the vicinity of Riddles, 

 Oregon, really belong, as Becker believed, at the top of 

 the section, their apparent extensiveness would justify their 

 being compared to the conglomerates of "Division i?" of 

 the Queen Charlotte Islands section ; and they might also 

 find their equivalents in the sections of California. 



V. Faunal Changes of the Cretaceous. 



I. Recognized Diversity. 



The work of Diller and Stanton has demonstrated how 

 little was previously known concerning the Cretaceous 

 series of California. From their study of the Cretaceous 

 deposits in the Sacramento Valley, they have felt compelled 

 to abandon the views of earlier writers regarding the com- 

 plexity of the series; while on the other hand, they have 

 emphasized the evidence of unbroken stratigraphic succes- 

 sion from bottom to top. Less effort has been made to 

 represent its actual diversification, either physical or faunal, 

 whatever this may be; and accordingly it remains to be 

 seen how far from simple were the conditions of deposition 

 in the Pacific border province during Cretaceous time ; yet 

 it appears that sufficient has been known for arriving safely 

 at conclusions somewhat different from those reached in 

 the accepted summary of our knowledge. 



It is entirely natural that the historical development of 

 the subject should be as it has been. Early collectors 

 working less thoroughly over the scattered deposits have 

 noticed the more striking dissimilarities without being able 

 to recognize connecting elements that a more detailed 

 study has discovered. Attention has been called to the 

 physical peculiarities of the Sacramento section of the Cre- 

 taceous, which shows on the whole a cycle of sedimenta- 

 tion somewhat the reverse of the normal. There is a certain 

 evidence in this fact that leads one to suspect that the 



