76 
ORIGIN OF LIFE IN AMERICA 
bring about the conditions of a Glacial Epoch. On the con¬ 
trary, it is evident that the opposite result would take place. 
The conditions of a Glacial Epoch, says Professor Whitney, 
are not to be sought for in a general diminution of tem¬ 
perature. “ It is true,” he argues, “ that the regions in which 
the glaciers take their rise cannot be so warm that precipita¬ 
tion takes the form of rain ; but the required low temperature 
must be confined to a limited area, and be brought about by 
local causes, and not be something in which all the other 
portions of the earth are sharers. There must be copious 
precipitation, which, although locally in the form of snow, 
can in reality only be the result of a high mean temperature 
in other regions. In short, warmth, as a phenomenon of 
general occurrence, is more indispensably necessary than cold, 
because the latter may always be produced, where locally 
wanted, by increase of elevation or by the shifting of the 
ocean currents.”* 
We now know that the glaciation of Alaska during the 
Ice Age must be regarded as an extension ,of the present 
system of glaciers. They were no doubt considerably larger, 
while glaciers also existed in the Endicott range in north¬ 
western Alaska. Nevertheless, no signs of former glaciation 
have as yet been discovered in the interior of the country. 
The latter is now generally believed to have been entirely 
unglaciated. If we adopted Professor Whitney’s views, and 
endeavoured to picture to ourselves the conditions of Alaska in 
the Glacial Epoch, we must imagine the Pacific to have been 
warmer than it is now and the climate of Alaska much milder 
and more humid. A more luxuriant flora would, under such 
circumstances, have been able to flourish in the interior of the 
country, and consequently a richer and more varied fauna. 
And how much is this conception of the Glacial Epoch at 
variance with the theories generally propounded! I may be 
excused, for example, for again citing Professors Chamberlin 
and Salisbury’s f words, that one of the most marvellous 
features of the ice-dispersion during the Glacial Epoch was 
* Whitney, J. D., “Climatic Changes,” p. 388. 
t Chamberlin, T. C., and R. D. Salisbury, “ Geology,” Vol. III. 
pp. 332—333. 
