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1915-16.] Opening Address by the President. 
Many of the interglacial deposits in North America do not furnish 
definite palaeontological evidence regarding fluctuations of climate during 
the Ice Age. The best sections are those near Toronto, Ontario, which 
have been minutely examined and described by Professor Coleman. They 
are exposed in the Don river valley and in the Scarborough cliffs, where the 
fossiliferous interglacial deposits reach a maximum thickness of 150 feet, 
the lower portion being visible in the Don valley and the upper in the 
Scarborough cliffs. They rest on boulder clay which has been referred to the 
Iowan Glacial Stage, though it might be of older date. Above the inter- 
glacial beds come sheets of boulder clay and assorted drift which are 
grouped with the Wisconsin stages. 
The flora and fauna obtained from the Don section indicate a warm 
climate, or, at least, conditions more genial than those of Toronto at the 
present day. The flora, according to Penhallow, who has identified a large 
number of species, points to a climate similar to that of the Central United 
States from 3° to 5° farther south. It includes the pawpaw ( Asimina 
triloba), the Osage orange, both of which now flourish in more southerly 
regions, the maple, the elm, ash, oak, hickory, and basswood. The fauna 
contains eleven species of unios, four of which are not recorded in the 
St Lawrence basin, but are now found farther south in the Mississippi basin. 
The flora and fauna in the higher interglacial beds on Scarborough cliffs 
imply a cold temperate climate resembling that now prevailing in the 
region north of Lake Superior. They doubtless indicate the gradual 
return of glacial conditions which characterised the earlier Wisconsin 
Glacial Stage. 
The older interglacial periods, viz. the Aftonian, the Yarmouth, and the 
Sangamon, are characterised by deposits of peat, indicating growth of 
vegetation, while the leaching of the materials and the denudation of the 
older drift imply prolonged intervals between the successive glacial stages. 
From the evidence summarised in the course of this address it is clear 
that the views advanced by J ames Geikie regarding oscillations of climate 
in Pleistocene time have been adopted by many investigators in Europe 
and America. Future research will show whether his elaborate classifica- 
tion of glacial and interglacial periods will have to be modified. Great 
diversity of opinion still exists regarding the interpretation of many glacial 
phenomena, the correlation of deposits in widely separated regions, and the 
sequence of conditions. But, in my opinion, sufficient palseontologica] 
evidence has been obtained to establish the general principle of oscillations 
of climate in the Glacial Epoch, though the number of interglacial periods 
may remain a subject of controversy. 
VOL. xxxvi. 
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