776 T. €. CHAMBERLIN 
so widely prevalent in the Permian and Triassic formations, this 
elevatory movement would stand in the proper relations. But, 
if present evidence is to be trusted, it does not stand in the 
proper antecedent relations to the Permo-Carboniferous glacia- 
tion, at least not as the primary agency. Still, though there is 
an absence of evidence of large exposure of the land surface to 
atmospheric degradation for a notable period preceding the 
Permo-Carboniferous glaciation, there are good grounds for 
believing that the great era-closing movement of the Paleozoic 
had made notable advance even at this time. 
The Gondwana elevation.—The glacial beds under considera- 
tion form the basal members of the remarkable Gondwana series, 
the chief members of which are land and fresh-water deposits. 
These in themselves imply a recently rejuvenated topography, 
for an ancient topography has a perfected drainage system and 
adjusted gradients. It is the dominant belief of those who have 
most studied the region circumjacent to the Indian Ocean, that 
the formation of the Gondwana series and the development and 
distribution of the remarkable Glossopteris flora, imply exten- 
sions and connections of land of a somewhat unusual kind. If 
this belief were accepted to the full extent urged by its strongest 
advocates, it would in itself involve a very large exposure. I am 
not disposed, however, to force the doctrine of a Gondwana 
continent beyond the most modest limits, however much it might 
contribute to a favorable reception of the hypothesis under dis- 
cussion. It appears to me that the distribution of the Glossop- 
teris flora may be in some notable part a climatic rather than 
a topographic effect; that is to say, the peculiar atmospheric 
conditions, of which glaciation was the supreme expression, dis- 
tinguished that quarter of the globe from the rest, and may in 
themselves have controlled the distribution of the peculiar flora in 
question. It may therefore only be necessary to postulate such 
an extension of the land as was required to permit the migration 
of the flora and its companion fauna. 
However this may be, it is very generally agreed that some 
notable land extension prevailed as early as the origination and 
