2A: GEORGE H. GIRTY 
seems to be indicated by the great reduction in the marine facies, 
especially in the brachiopod representation, so that in the Permian 
there remains scarcely a tithe of the greatly diversified brachiopod 
fauna of the Gschelian, and by the introduction of fresh-water types 
of which not less than 200 species have been recognized. Apparently 
the typical Permian deposits of Russia represent local and not normally 
marine conditions of deposition. 
I am tentatively assuming, on the grounds noted above, that the 
Guadalupian is equivalent to the Permian or to the Permian and 
Artinskian, the one representing a normal marine and the other an 
abnormal facies. It may prove, however, that all or part of the 
Guadalupian is younger than the Permian. <A recent monograph by 
Tschernyschew gives a complete account of the brachiopods of the 
Gschelian, but the other types remain undescribed or else the descrip- 
tions are badly scattered. The literature on the Artinskian and Per- 
mian is also somewhat scattered, but one receives the impression 
that the brachiopods of the latter do not present many positive differ- 
ences from those of the Gschelian though much less varied, and 
reduced to a few types of long range and wide distribution. Whether 
the same is true of the rest of the fauna it is difficult to say, although 
it seems rather doubtful. In view of the striking difference between 
the faunas of the Guadalupian and the Hueco formation, in which the 
brachiopods are most in point, of a lack of a corresponding difference 
between the Gschelian and Permian, of the marked resemblance of the 
brachiopods of the Hueco and Gschelian, and of the lack of agreement 
between the Permian and Guadalupian, there is a possibility, if not 
a certain probability, that the Artinsk and Permian may be correlated 
with the Hueco formation. 
Having compared the western faunas with those of Russia, let us con- 
sider what their relations may be with those of eastern North America. 
We find in such a comparison really fewer resemblances than with 
the faunas of Russia. Of the three or four western faunas which 
I have noted, by far the greatest resemblance is to be found in the 
oldest of all; perhaps because it is least varied and most generalized. 
The Hueconian presents much more numerous and extensive differ- 
ences and the Guadalupian the strongest of all. In fact, of the 325 
species recognized in the latter scarcely a single variety can be definitely 
