EQUIVALENCE OF BEDS IN EASTERN AND PLAINS PROVINCES 225 



Appalachian trough, is present at most of the localities, while Callipteris, which 

 is very meagerly represented in eastern North America, is common and highly 

 differentiated in Kansas and Colorado. Gomphostrobus, another type char- 

 acteristic of the Permian of western Europe and hitherto unknown in North 

 America, is present in Kansas, Colorado, Oklahoma, and Texas. The common 

 type of simple-leafed Tceniopteris, diagnostic of the western European lower 

 Permian, is nearly everywhere present, sometimes accompanied by other forms, 

 one of which, with distant, simple nerves, is of distinctly Mesozoic aspect. 



"In addition to the many Callipteris and Walchia species just mentioned, the 

 provisional lists from the western Permian include a number of other forms near 

 to, if not identical with, diagnostic Old World Permian types hitherto unknown in 

 this continent. Among these are Schizopteris cf. trichomanoides, Sphenopteris 

 lebachensis, Pecopteris geinitzi, Pecopteris pinnatifida, Cladophlebis? cf. tenuis, 

 Scolecopteris elegans, Odontopteris subcrenulata, Tceniopteris abnormis, Annular ia 

 spicata, Rhabdocarpos cf. dy adieus. 



"It is probable that several cosmopolitan species of Pecopteris and Sphenop- 

 teris will be found to have accompanied Tceniopteris multinervis from western 

 Europe to eastern China. 



"The examination of the materials from the Western Interior and Rocky 

 Mountain basins shows that while the flora is composed mainly of types common 

 to western Europe which have undoubtedly been distributed along essentially the 

 same northeastern Arctic- American route by which the Pennsylvanian floras 

 migrated, it contains also a somewhat unique element unmistakably derived from 

 eastern Asia. The latter includes the Gigantopteris, the peculiar Annular ia, 

 and a Tceniopteris form, to which should possibly be added the representatives 

 of Araucarites and Neuropteridium. The migration of this land-plant element 

 was very probably by the north Pacific. 



"The most important deduction to be drawn from the occurrence of Gigan- 

 topteris and its particular associates in North America is the essential continuity 

 of environmental conditions indicated thereby. The vital conditions under which 

 the types lived in Oklahoma and Texas can not have been very far different in 

 their essential respects from those prevailing in the Chinese habitats of the types. 

 Environmental conditions sufficiently uniform to enable these plants to thrive 

 must have attended the route of their land migration. We may therefore con- 

 clude that a climatic environment essentially similar extended from China to 

 western North America; that is, that during Gigantopteris time western North 

 America and portions of eastern Asia were probably included in the same climatic 

 province. The mingling of the western European flora with the Chinese elements 

 in Oklahoma and Texas suggests that the latter region may have been on the 

 eastern border of the province. 



"Another interesting feature of the western Permian is the presence of fronds 

 possibly identical with Psygmophyllum cuneifolium, Odontopteris permiensis, Odon- 

 topteris fischeri, and Sphenophyttum stoukenbergi, species that seem not to have 

 been known outside of the Uralian region, from which they were described. 

 Possibly the remarkable Kansas type described by Sellards 1 as Glenopteris, which 

 is unlike any European type of its period, and which may be nearest related to the 

 Neuropteris salicijolia of Morris, also is of Uralian or Asiatic descent. The types 

 of Uralian origin also may have reached western North America by the north 

 Pacific route. 



1 Kansas University Quarterly, volume 9, 1900, p. 179. 

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