UNIVERSITY OF OREGON PUBLICATIONS 

 Vol. I August, 1920 No. - 



FOSSIL MOLLUSKS FROM THE 



JOHN DAY BASIN IN 



OREGON 



CONTAINED IN THE CONDON MUSEUM OF THE 

 UNIVEESITY OF OEEGON 



BY 

 G. DALLAS HANNA 



CONTENTS 



Introduction. 



Species in the University of Oregon Collection. 

 Synopsis of John Day Land and Fresh-water Mollusks. 

 Explanation of plate. 



INTRODUCTION 



Through the courtesy of Dr. Earl L. Packard, of the Depart- 

 ment of Geology, University of Oregon, I have had an opportunity 

 to study the collection of fossil land shells in that institution from 

 the John Day Basin, eastern Oregon. It was assembled by Prof. 

 Thomas Condon, the discoverer of the famous deposits of mammal 

 remains in Oregon. Altogether there are 118 specimens in the col- 

 lection. Many of them are fragmentary or immature and cannot be 

 identified with certainty. Eleven species are represented, two of 

 which are believed to be new. These belong to genera found for the 

 first time in the Miocene deposits of the western United States and 

 one of them was not previously known to exist in North America, 

 either Recent or fossil. The collection also includes specimens of 

 species which were previously known only from type specimens. 

 The collection is therefore one of the most important which has 

 come to light from this region. 



In order that references to all of the described John Day 

 species may be available to western students there has been added 

 to the account of this collection a review of all known published 

 records. This has been compiled from the author's card index. 



[1] 



