FOSSIL LAND SHELLS OF THE JOHN DAY REGION 657 



13403) of this interesting and curious form. It is apparently the 

 forerunner or ancestor of the living A.yaiesi described by Dr. Cooper 

 from specimens collected by Dr. L. G. Yates in the cave at Cave City, 

 Calaveras County, California, in 1869. 



As Dr. Cooper remarks " it would have been supposed to be a 

 Planorbis if found near water and if the streams of that country had 

 not been thoroughly searched by many collectors. It resembles Plan- 

 orbis in the inverted spire and in the partial enclosure of each whorl 

 in the next larger, so that the spire shows only a small portion of the 



whole shell." 



The fossil examples are all imperfect, but taken together they show 

 quite satisfactorily its specific and generic relations. I have compared 

 them with a good series of specimens contained in the National Mu- 

 seum ; though the fossil specimens are considerably larger than any of 

 the recent ones, I am unable to detect any other difference. The geo- 

 graphical range of the living or recent yatesi, though quite restricted, 

 fs much greater than at first reported. It was supposed to be confined 

 to the interior or immediate vicinity of the cave; subsequently Mr. 

 Hemphill,^ the well-known collector, found it " near Murphy's (in the 

 same county), seven miles away from the cave, sestivating under stones 

 or north hill-sides, while numbers of dead shells lay bleaching in the 

 sunshine," etc. The late Mr. C. D. Voy also collected it elsewhere 

 than at the cave. The restricted distribution of A. yatesi and the 

 smaller size of the recent, compared with the fossil examples, suggest 

 obsolescence, as well as a survival of the extraordinary physical changes 

 of the John Day Epoch. The absence of other forms, which might 

 prove connecting links with existing allied species, may be due to 

 absolute obliteration through similar causes during the middle or later 

 Tertiary periods, or even still later physical changes. 



Family ENDODONTID^ Pilsbry. 



Genus Pyramidula Fitzsinger 1883. 



PYRAMIDULA PERSPECTIVA SIMILLIMA Stearns. 



(Plate XXXV, fig. 7-) 



Helix {Patula) perspectiva Say (Stearns) Bull. 18, U. S. Geol. Survey, p. 

 14, pi. Ill, fig. 7. 1885. 

 The collections contained only one example of this form, and this 



1 Zoe, Vol. Ill, p. 45. San Francisco, April, 1892. 



