UPPER CARBONIFEROUS 319 
the evidence at present is so inconclusive that dogmatism itself would 
be ill-advised. At present, it is true, the weight of evidence, as pre- 
sented by invertebrate paleontology, appears to me to be in favor of its 
pre-Permian age. This view has much of precedent against it, 
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 with the subdivisions recognized in the Mississippian 
than co-ordinate with the larger groups such Mississippianand Pennsyl- 
vanian. 
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. 
