UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 5, No. 28, pp. 413-420 ANDREW C. LAWSON, Editor 



THE PROBABLE TERTIARY LAND 

 CONNECTION BETWEEN ASIA 

 AND NORTH AMERICA.* 



BY 



ADOLPH KNOPF. 



INTRODUCTION. 



A land connection between northeastern Asia and north- 

 western America during a portion of Tertiary time has been 

 postulated by paleontologists to explain certain faunistic prob- 

 lems. It has been accepted as probable and so charted on Willis' 

 paleontologic map of Miocene North America. 1 



The present paper, which is partly based on personal famil- 

 iarity with northwestern Alaska, undertakes to discuss the 

 geologic evidence of such a land connection. 



The portion of Alaska lying nearest to Asia has been desig- 

 nated the Seward Peninsula since the gold excitement of 1898, 

 and a great increase in the geographic and geologic knowledge 

 of that region has resulted from the investigations conducted by 

 the United States Geological Survey subsequent to that date. 2 

 As those studies have concerned themselves mainly with the 

 auriferous alluvia, many observations bearing upon broader geo- 

 logic problems are scattered through the numerous economic and 

 progress reports, where they are not readily available to those 

 unfamiliar with the literature. 



* Published by permission of the Director of the U. S. Geological 

 Survey. 



1 Journ. GeoL, 1909, p. 503. 



2 Bull. U. S. Geol. Survey No. 328, 1908, contains a compendium of the 

 geography and geology of Seward Peninsula. 



