106 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
though in the Triassic time vfents abounded along these shores. This 
taken in connection with the fact that the sea bottom along these 
shores is the seat of rapid sedimentation leads us to the conclusion 
that the continent has recently had a much greater eastern extension. 
At other points we may in like manner infer the approximate stability 
of a shore line by the long continuance of volcanic activity in the 
same field. 
