THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. XIIL] MAY, 1920. [No. 1. 



Miocene Land Shells from Oregon.* 



BY G. DALLAS HANNA, 



Curator of Invertebrate Paleontology, California Academy of Sciences. 



(Plate I.) 



THE exposures of fossiliferous rocks in the valley of the 

 John Day river in Oregon have been known as a collecting 

 ground for mammalian remains since 1861. Many expeditions 

 have worked there and an extensive literature exists in which 

 numerous types have been described. Fossil mollusks were 

 obtained by the earliest collectors and subsequently and sev- 

 eral papers have been written about them since 1870. 



In 1907 an expedition was led into the region by Mr. H. T. 

 Martin, curator of paleontology of the University of Kansas. 

 Numerous specimens of vertebrate animals were secured and 

 Mr. Martin also collected the land shells which form the basis 

 of this report. Sixteen specimens belonging to eight species 

 were found at Cove Inlet of John Day river. Four species 

 appear to be new and are named and described herein. 



Altogether thirteen species of mollusks have been collected 

 in the John Day deposits, eleven being land pulmonates, one a 

 fresh-water pulmonate and a fresh-water mussel. All are spe- 

 cies not now known to exist but no genus has been considered to 

 be new. The preponderance of the land forms has an inter- 

 esting bearing upon the question of the lacustrine, fluviatile 

 or seolian method of deposition of the strata.f 



* Received for publication on February 2, 1920. 



t For a full account of the geological, stratigraphical, and paleontological features of 

 the region see. Merriani, "A Contribution to the Geology of the John Day Basin," Uni- 

 versity of California publications, Bulletin of the Department of Geologv, vol. 2, No. 9, 

 pp. 269-314, April, 1901. Also, same author and series, vol. 5, No. 1, pp. 1-64; De- 

 cember. 1906. Also, vol. 5, No. 11; Merriam and Sinclair for fairly complete bibliography, 

 etc.; October, 1907. 



(3) 



