Vol. 6] Merriam: Virgin Valley and Thousand Creek. 



271 



in definitely referring the Virgin Valley ehalicotheres to any of 

 the known species. Especially is this difficult owing to the frag- 

 mentary nature of the types of the species, M. distans and M. 

 senex, described by Marsh from the John Day region, which is 

 separated by only a short distance from Virgin Valley. The 

 Virgin Valley form is presumably very near if not identical with 

 some of the forms already described. If some of the material 

 from the John Day region should prove to have been derived 

 from the Mascall formation there would be reason to suspect 

 that the Virgin Valley species is nearly related to it. If all of 

 the material from the John Day Valley is from the John Day 

 formation specific identity is improbable. 



Occurrence: Virgin Valley Beds, localities 1065 and 1095, 

 Virgin Valley, Humboldt County, Nevada; also from High Rock 

 Canon and Little High Rock Canon, Humboldt County, Nevada. 



PROBOSCIDEA 

 MASTODON (TETBABELODON "?, sp.) 



Remains of proboscideans were found frequently both at 

 Thousand Creek and Virgin Valley. In Virgin Valley they were 

 obtained in the highest horizons in which fossil remains were 

 seen, and also occurred well down in the section, though possibly 

 not at the lowest horizon at which collections were made. 



Figs. 46 and 47. Mastodon (Tetrabelodon ?, sp.). Portions of cheek 

 teeth. No. 19445, X V-±. Virgin Valley Beds, High Bock Canon, Nevada. 



