UPPER PALEOZOIC FLORAS Bey 
account of the strange character of the flora, I am inclined to regard 
the peculiar floral association as due to the extension of the early 
Gondwana climatic influence into north-central Asia and the subse- 
quent isolation of the flora from western influences. This theory is 
supported by the presence of the older Gondwana flora in the coalfield 
of Shensi in China. On the other hand the floral differences between 
the Ural and eastern localities may be due to geographic position of the 
latter in the interior of the great Asiatic continent while the Ural 
flora which has more elements in common with the western world is 
located on the west coast of this continent. 
The contrast is certainly not due to mere latitude, nor can it be 
credited wholly to aridity; for the eastern plants are associated in 
great series with coals in each region. A few stray wood fragments 
of uncertain location and age appear to offer slight evidence of sea- 
sonal changes, but the criteria deserve careful re-examination both 
as to this point and as to the geological horizon of the material 
described. . 
It would be most interesting to know to what extent the plant life 
of Permian time on the west coast of North America was influenced 
by the Gondwana glacial climate and as to how far it was allied to the 
older Gondwana floras. 
The sharp contrast between the Chinese Gondwana plants and 
the floras of the very latest Stephanian in the same region involves 
a pronounced break either in climate or in time in that quarter of the 
globe. Probably both are concerned. ‘The most satisfactory illumi- 
nation of the stratigraphical and paleontological history of this 
period will probably be found in China or southern Siberia. 
“ PERMO-CARBONIFEROUS CLIMATES ”’ 
Climate oj the Carbonijerous.—The climate of the Pennsylvanian 
(“Upper Carboniferous”) as viewed in perspective was mild and 
relatively humid, and, above all, equable over the greater part of 
the earth. It was moderate in temperature, not tropical, possibly 
not even subtropical, but, during the Westphalian at least, always and 
everywhere equable. It was truly temperate. The criteria which may 
be interpreted in support of this generally accepted proposition in- 
clude: 
