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



The fossil remains found in most of the Cretaceous 

 deposits throughout this vast stretch of continental border 

 show them to be for the most part of marine, and of littoral, 

 rather than of deep-sea origin. 



II. Historical Review. 



No other series of rocks upon the Pacific Coast has 

 received so much attention as those of the Cretaceous 

 period. It is perhaps due to their easy accessibility, and 

 to the extremely interesting character of their fauna, that so 

 many able contributions have been made to the literature of 

 West Coast Cretaceous. Yet we are far from knowing all 

 that is desirable concerning the stratigraphy and fauna of 

 this interesting period. 



A brief review of the more important papers that have 

 appeared from time to time, and accordingly a summary 

 sketch of the development of our present knowledge of the 

 subject, is here included for the benefit of readers who may 

 not be familiar with what has already been done. 



The first announcement of Cretaceous deposits in Cali- 

 fornia was by Dr. Trask (1856), in which he reported the 

 discovery of ammonites and baculites in " Tertiary strata." 



Eight years later, in 1864, the first volume of the Paleon- 

 tology of California appeared, in which Mr. Gabb pub- 

 lished a large number of species from strata which he 

 designated as Divisions yl. and ^. of the Cretaceous series. 

 These are now known as distinct formations of Cretaceous 

 and Tertiary age. Afterwards, in the second volume of the 

 Paleontology of California, which appeared in 1869, Gabb 

 distinguished four horizons of the Cretaceous, which he 

 called respectively Shasta, Chico, Martinez and Tejon, the 

 last two of which are now known to be Eocene, or only in 

 part Cretaceous, as shown later. 



The beds exposed at Horsetown, and along the North 

 Fork of the Cottonwood Creek, Shasta County, constituted 

 what was termed the Shasta Group. It was stated that it 

 contained fossils representing the ages from the Gault to 

 the Neocomian, inclusive, of the European Cretaceous. 



