UPPER CARBONIFEROUS 315 
identified in the eastern faunas. The species are in most cases not only 
not the same but they are not even similar. It seems possible to me 
that the Hueconian fauna may be equivalent, in spite of its differences, 
to the faunas of the East, but hardly that of the Guadalupian. This 
opinion is based upon the striking differences existing between the 
Guadalupian and any eastern fauna, upon the much closer resem- 
blance of the eastern faunas with the Hueconian fauna, and upon the 
important differences between the latter and the Guadalupian. How- 
ever, as so little is known of the character and potency of the environ- 
mental conditions under which these faunas existed, there is a possi- 
bility which I do not wish to deny that the relations noted may have 
to be ascribed to the environment element, rather than to the time 
element. 
Provisionally I am regarding the Guadalupian as younger than 
any known faunas of the eastern region, thus interpreting the faunal 
differences of the Hueconian when compared with the Pennsylvanian 
and Permian of the East, as due to environment rather than to time. 
There is some evidence, however, that the Hueco formation should be 
considered younger than the so-called Permian of the Kansas section 
instead of equivalent to it. Mr. Beede has recently described several 
occurrences of a fauna which I should perhaps have mentioned as 
representing one of the interesting and important differentiations 
found among the faunas of the Upper Carboniferous of the East. 
They were obtained from the red beds of Oklahoma and the horizon 
is known to be considerably above the highest occurrences of inverte- 
brate fossils in Kansas. This fauna appears to me to present more 
important differences from the Kansas Permian than exist between 
the latter and the underlying beds referred to the Pennsylvanian. 
Accordingly, if any of the faunas of the eastern section are to be classed 
as Permian it would appear to me more appropriate that the dividing 
line should pass above rather than below the Kansas Permian. 
When compared with the western faunas, that described by Mr. Beede 
is far from being identical either with the Guadalupian or with any 
facies of the Hueconian, but of the two its affinities appear to be decid- 
edly with the latter. If this evidence is to be relied on, even Mr. 
Beede’s fauna is older than the Guadalupian and if the latter is equiva- 
lent to the Permian, older than the Permian. 
