UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 9, No. 12, pp. 137-159, 1 map Issued February 8, 1916 



FAUNAL STUDIES IN THE CRETACEOUS 

 OF THE SANTA ANA MOUNTAINS OF 



SOUTHERN CALIFORNIA 



XjaYvSO nun } n ^> 



BY 



EAEL LEEOY PACKARD 



APR 2 4 1917 



CONTENTS 



PAGE 



Introduction 137 



Review of the Literature 138 



Geology of the Region 139 



General Geologic Relations 139 



The Trabuco Formation 140 



The Chico Group 141 



Fauna 142 



General Character 142 



Faunal Zones 143 



Relation to other Cretaceous Faunas of California 150 



Relation to Foreign Cretaceous Faunas 156 



Age 157 



Summary 15S 



Introduction 



The large number of fossiliferous localities oecuring within the 

 Cretaceous beds flanking the western slope of the Santa Ana Mountains 

 afford an unusual opportunity for faunal studies in the Upper Cretace- 

 ous of the Pacific Coast. Detailed studies of the faunal successions in 

 this region were carried on by the writer in connection with the work 

 of the University of California Summer Session class in Palaeontology 

 in 1913. Collections in the Cretaceous were made at seventy-two 

 localities, for nearly all of which the stratigraphic position is definitely 

 known. These stations are well distributed throughout the two thou- 

 sand feet of strata in the section and are situated along a strip about 



