188 
ELEMENTS OF GEOLOGY. 
ers, that the abrading action of ice has formed some mount¬ 
ain tarns and many morainic lakes; but when it is a question 
of the origin of larger and deeper lakes, like those of Swit¬ 
zerland or the north of Italy, or inland fresh-water seas, like 
those of Canada, it will probably be found that ice has play¬ 
ed a subordinate part in comparison with those movements 
by which changes of level in the earth’s crust are gradually 
brought about. 
