ICE-PERIOD IN AMERICA. 
81 
from them as in Europe. During the greatest 
extension of the ice-fields, there were but few 
prominent peaks rising above them, and drop¬ 
ping here and there huge boulders on their 
surface, to be transported to great distances 
without losing their rough angular character. 
When the temperature under which these vast 
frozen masses had been formed rose again, the 
wasting ice must have yielded first on its 
southern boundary, gradually and uniformly 
retreating to the Arctic regions, without break¬ 
ing up into distinct glacial regions, separated 
from one another, each with its local distri¬ 
bution of erratic boulders and glacier-marks 
radiating from circumscribed areas on higher 
levels as they occur everywhere in Europe. It 
is true that there are a few localities within 
the Alleghany range, on the Green and White 
Mountains, and in parts of Maine, where it is 
evident that local glaciers have had a tempo¬ 
rary existence; but even throughout this east¬ 
ern coast-range the elevation of the mountains 
is so slight, and their trend so uniform in 
a northeasterly and southwesterly direction 
through twenty degrees of latitude, that the 
localization of the phenomena is less marked 
4 * 
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