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INTRODUCTION. 
BY 
J. W. GOLDTHWAIT. 
The purpose of this excursion is to study certain 
records of submergence of the St. Lawrence valley by the 
sea at the close of the Glacial period. The evidences of 
this submergence are both geologic and physiographic. 
Clays containing marine shells of an arctic or sub-arctic 
fauna will be seen at altitudes a few hundred feet above 
the present level. Wave-built beaches, marking the former 
stand of the sea against the hillsides will be visited and 
critically examined at various altitudes up to 570 feet. 
Particular attention will be given to the determination 
of the upper limit of submergence. 
Of the three localities visited, Montreal lies on an 
ancient island of the Pleistocene sea, near the middle 
of what was then the great St. Lawrence embayment. 
Covey hill lies on the south shore of this Pleistocene 
estuary in acritical position with reference to earlier, higher 
water levels; for while the ice sheet still rested against 
its northern slope great pro-glacial lakes occupied the 
valleys of Lake Ontario and Lake Champlain. Ottawa lies 
far up one of the long arms of the Pleistocene embayment, 
on the north side. Here, as well as in the other localities, 
the relation of the marine sediments to the earlier, ice-laid 
deposits will be seen. 
On the outline map which accompanies this guide, 
the south shore of the ancient Champlain Sea is shown 
from the City of Quebec to Lake Champlain and the 
Adirondacks; also the altitudes of the highest marine 
beach, in feet above sea level, at several localities in this 
district. 
