UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 10, No. 7, pp. 87-109, 23 text-figures Issued November 1, 1916 



AN AMERICAN PLIOCENE BEAR 



BY 



JOHN C. MEREIAM, 

 CHESTER STOCK, and CLARENCE L. MOODY 



CONTENTS 



PAGE 



Introduction 87 



Occurrence - - - 88 



Dentition 90 



Skeletal Elements 97 



Relationships 105 



INTRODUCTION 



Although the bear group is well known in some of the latest 

 Cenozoic faunas of the Western Hemisphere, the one or two occur- 

 rences of very fragmentary material reported to represent this family 

 in American deposits older than Pleistocene have been considered 

 doubtful. In the Old World, members of the Ursidae are found in 

 formations ranging from Miocene to Recent, and in view of available 

 evidence it is assumed generally that the New World bears are com- 

 paratively recent immigrants, the earliest arrivals having come from 

 Asia to North America near the beginning of Pleistocene time. 



The North American Pleistocene bears comprise two groups ; the 

 Ursus type, represented by forms closely related to existing species of 

 this continent; and the peculiar short-faced arctotheres, having no 

 living representatives in North America, but closely related to the 

 spectacle bear of South America. In the Pleistocene of South America 

 Arctotherium is known by several species, but Ursus is not represented. 

 There is then apparent basis for the theory that Arctotherium arrived 

 in North America in advance of bears of the Ursus type and reached 



