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



239 



but is slightly shorter and is a little narrower posteriorly. It is 

 hardly to be distinguished from T. kelloggi and may be referred 

 to that species tentatively. 



Occurrence: Thousand Creek Beds; locality 1103, Thousand 

 Creek, Humboldt County, Nevada. 



In the collection from Little High Rock Canon there is a frag- 

 ment of a lower jaw (figs. 8a and 85) with P 4 and M 1 which 

 represents a canid. This specimen, no. 12503, differs in form 

 and dimension of P 4 and Mj from the type specimen of T. 

 rurestris. P 4 is a rather heavy tooth with both posterior cusp 

 and basal tubercle. As in T. rurestris there is no anterior basal 

 tubercle. In Mj the metaconid seems relatively smaller than 

 in the typical species, but it is not easy to judge of this character 

 with absolute certainty, as the two teeth are not available in the 

 same stage of wear. The heel of M 1 is wide, while the hypoconid 

 and entoconid are of nearly equal size. 



Mj of this form may differ from T. rurestris in acuteness 

 of the protoconid and paraconid, and in smaller size of the 

 metaconid. Otherwise the resemblance is very close. As no. 

 12503 has an absolutely unworn M 1; while in the type of T. 

 rurestris this tooth is considerably worn, the difference may 

 appear slightly exaggerated. It is desirable to have M 2 repre- 

 sented before attempting to establish the identity of the two 

 forms with certainty. 



Occurrence: Virgin Valley Formation; locality, Little High 

 Rock Canon, Humboldt County, Nevada. 



Measurements, No. 12542. 



M 2 , anteroposterior diameter 



M 2 , greatest transverse diameter 



9.9 mm. 



5.7 



TEPHROCYON( ?) , compare RURESTRIS (Condon) 



Measurements 



P 4 , anteroposterior diameter 



P 4 , transverse diameter 



M 1; anteroposterior diameter 



M 1; anteroposterior diameter of heel 



M„ transverse diameter of heel 



Height of mandible below protocone of Mj 



Type of T. 

 rurestris 



11.5 mm. 



No. 12503 



11.7 

 6.3 



22.3 

 6.4 

 8.4 



6. 

 20. 

 6. 



20. 



