218 GEORGE H. GIRTY 
eastern North America must have remained essentially static until 
similar conditions, setting in in Perm and in Kansas, eventually 
extinguished those already moribund faunas, while the intervening 
faunas, those of western America, remained vigorous and rich. The 
considerable differences found between the Russian Permian and the 
Kansas Permian faunas would, according to this hypothesis, be 
explained as due to the play of like conditions upon unlike organic 
bases, the pre-Permian faunas in the one region having changed, 
and those in the other having remained unchanged. But this appears 
to me improbable. One would hardly expect that the Pennsylvanian 
fauna would remain static during so long a period in which such 
important faunal changes were taking place in adjacent areas. Nor 
would one expect that Permian conditions would be inaugurated 
simultaneously in two areas so far apart, whose biologic histories are 
so different, and which were separated by an area having a more or 
less independent set of faunal phenomena. Finally, if the Kansas 
Permian is Permian, what is the fauna from the Oklahoma red beds, 
obtained at a considerably higher horizon, and showing a consider- 
ably different facies ? It does not seem probable to me therefore that 
the Kansas Permian and the Russian Permian were contemporaneous. 
An extreme interpretation of the resemblances and differences 
noted in comparing the successive faunas of Russia and eastern North 
America would result in correlating the Kansas Permian not with the 
Russian Permian, as in the last hypothesis, but with the Moscovian. 
In this case the quasi-Permian facies:of the upper beds of Kansas 
would be accounted for as showing the yield of an unlike and older 
fauna to Permian conditions which arrived on this continent at a 
much earlier period than in Russia, just as in the previous case the 
differences of the same fauna from the typical Permian would be ex- 
plained as the opposite or complementary phenomenon, the resistance 
of an unlike fauna to Permian conditions. Probably the ultimate 
fact lies somewhere between these two extreme interpretations of the 
evidence. 
I do not wish to appear as having a rooted aversion to admitting 
the Permian age of the higher faunas of the Kansas section. My 
position is merely that of a skeptic and the only point upon which 
I feel justified in assuming the positive attitude of dogmatism is that 
