202 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [ToT^fVL 



From the above it is evident that the Wind Eiver fauna -in- 

 cludes genera which have been hitherto restricted to either the WSr 

 satch or Bridger lists. Of these, especially Bridger genera, there arei 

 six; that is, six genera which have not yet been detected in beds of the 

 Wasatch epoch. On the other hand, there are nine genera which have 

 been found in Wasatch beds and not in those of the Bridger. Three 

 important Wasatch genera have not been found in the Wind Eiver 

 formation, while seven of the characteristic genera of the Bridger are 

 not included in the list of those of the Wind Eiver. The result, imper- 

 fect as it is, indicates a considerably greater conformity to the Wasatch 

 epoch than to the Bridger in the faunal characters of the Wind Eiver 

 beds, and points to the confirmation of Dr. Hayden's views as to the 

 identity of the two epochs. 



The new species above described will be fully illustrated in the fourth 

 volume of th^Eeport of the United States Geological Survey of the Ter- 

 ritories, F. V?Hayden in charge, now passing through the press. 



