226 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



"According to their composition and relations the floras of the younger 

 Carboniferous in Shansi and Sheng-King, or Manchuria, which are either at the 

 latest Pennsylvanian stage or in the early Permian, may with probable safety 

 be assumed to have antedated the early Gondwana glaciation and the existence 

 of the Gangamopteris flora in southern Asia. The question arises, then, whether 

 the floral peculiarities of the Gigantopteris province are due in part to climatic 

 changes leading to refrigeration in India, and whether later the climate of the 

 Gangamopteris province extended over a portion at least of the Gigantopteris 

 province, and if so, whether it did not cover a part of western North America." 



And further, on page 513: 



"The very incomplete collections of fossil plants from the Wichita formation 

 in Texas, from its supposedly approximate equivalents in Oklahoma, from the 

 .Chase and Sumner groups in Kansas, and from the great series of undifferentiated 

 ' red beds ' in the Rocky Mountain region of southern Colorado, show a mixed 

 flora embracing (i) mainly representatives of the Permian flora of western 

 Europe, and including many types not previously known in North America; 

 (2) a smaller portion peculiar to the Gigantopteris association in south central 

 and southwestern China; and (3) several types apparently identical with or very 

 close to forms hitherto known only in the Permian of the Uralian region. 



"The distribution of the floral elements indicates that the western European 

 or cosmopolitan elements of the flora migrated between North America and 

 Europe, presumably by the same general northeastern route as that followed by 

 their Pennsylvanian predecessors, while the distinctly Chinese types must have 

 come to Texas and Oklahoma by the north Pacific (Alaskan) route, by which the 

 related Uralian forms may also have migrated. Since the land migration of the 

 Chinese types could hardly have been accomplished without the aid of essential 

 continuity of environmental conditions, and since it is probable that the Gigan- 

 topteris elements lived under climatic conditions mainly similar in both Texas 

 and China, the conclusion appears justified that the climatic province under 

 which they thrived in Asia extended to western North America and that it 

 included the region of noith Pacific migration. The mingling of western Euro- 

 pean species with Gigantopteris in the southwestern 'red beds' is construed to 

 indicate that this region was probably on the eastern border of the Gigantopteris 

 province." 



Sellards^ says of the flora of the Wellington shales: 



"The flora of the Wellington differs in toto, so far as species are concerned, 

 from that of the Cherokee shales, and contains only a small proportion of species 

 found in the Douglas formation. Of the species listed from the Wellington only 

 a few have been positively Identified with forms found In the Le Roy and Lawrence 

 shales. More than two-thirds of the Wellington species are either Identical with 

 or most closely related to species or genera characteristic of the European Permian. 

 The points which seem to have the most importance as bearing on the correlation 

 of the Wellington are the following: (i) The complete absence of species in any 

 way confined to or distinctive of the Coal Measures. (2) The comparatively 

 small number of species originating as early as Upper Coal Measures time. (3) 



^ Sellards, E. H., Fossil Plants of the Upper Paleozoic of Kansas, University of Kansas 

 Geological Survey, volume ix, p. 462, 1908. This is a final paper; preliminary papers 

 were published in the Kansas University Quarterly, volumes 9 and 10, 1900-1901. 



