138 GEORGE H. GIRTY 



although it has considerable authority in its support. It will be 

 remembered that some half century ago there was a conscious and 

 competitive attempt between a number of invertebrate paleontolo- 

 gists to discover the presence of Permian rocks in our then western 

 states. From this the correlation of the Kansas beds with the Russian 

 Permian took its rise. I am inclined to believe that were the investiga- 

 tion of this subject taken up on its merits from the richer accumulations 

 now available, and not compromised by this early rivalry, few if any 

 would think of separating the upper formations of the series from the 

 lower, or, if a separation were thought of, the divisions would be held 

 rather to rank wnth the subdivisions recognized in the Mississippian 

 than to be co-ordinate with the larger groups such as Mississippian and 

 Pennsylvanian. 



At all events, it appears to me from such evidence as I have 

 seen, that the Russian Permian represents peculiar, one may perhaps 

 say abnormal, conditions which were probably local or regional in 

 extent. That Permian time is represented by our sediments seems 

 undoubted; that Permian conditions prevailed here is attested by 

 good witnesses; that Permian conditions occurred here in Permian 

 time seems to me open to question, and that any of our known faunas 

 present the authentic Permian facies, I do not believe. Consequently 

 the propriety of employing the term Permian in the geology of North 

 America seems to me decidedly doubtful, at least in so far as the evi- 

 dence of invertebrate fossils is concerned. It would be better, I believe, 

 to use the term Permian wherever the Permian fauna can be traced 

 and no farther ; to use the term Pennsylvanian wherever the Pennsyl- 

 vanian fauna can be traced and no farther; to use the term Guada- 

 lupian wherever the Guadalupian fauna can be traced and no farther ; 

 but, if, for instance, it could be shown that for all their faunal differ- 

 ences the Gschelian and Pennsylvanian were contemporaneous, to use 

 for both the same name, whether Pennsylvanian or Gschelian, would 

 be to obscure and gloss over facts of biology, climatology, and possibly 

 geography, fully as important as that of chronology. 



