554 The Formation of Cape Cod. [September, 
The removal of the water thus taken from the sea and stored up 
in accumulations of ice would lower the surface of the ocean 
more than a half mile. At the same time this vast accumulation 
of ice in high latitudes must draw the sea by gravitation away 
from the equator toward the poles. This cause appears to have 
retained the sea-level at about its present height near the lower 
limit of the ice-sheet, while in arctic regions it rose much higher 
than now. Marine shells in the modified drift show that the sea 
thus stood fifty to two hundred feet above its present height on 
the coast of New Hampshire and Maine; five hundred feet in the 
valley of the St. Lawrence, and one thousand to two thousand feet 
higher than now along the west coast of Greenland. Everywhere 
in high latitudes, both in the northern and southern hemispheres, 
we have proof of such a submergence of the land when the drift 
was accumulated, increasing in amount the nearer we go to the 
poles. On the other hand, the coral islands of the tropics are 
witnesses of the depression of the sea in this period, amounting 
to three thousand feet, or perhaps more, at the equator, while 
different evidence shows that at the mouths of the Mississippi, 
Ganges and Po rivers it was at least four hundred feet lower than 
now. If we reflect upon these widespread changes of sea-level 
that marked the glacial period, occurring only where they would 
be produced by taking water from the sea to form ice-sheets and 
by gravitation through their influence, and if we compare these 
recent simultaneous changes with the general stability of the con- 
tinents, we seem compelled to attribute them to movements of the 
sea rather than of the land. 
Because of the attraction of accumulations of ice that still 
remain about the poles, where probably little or none existed in 
Tertiary times and at the epoch immediately preceding the glacial 
period, the sea along the eastern coast of the United States 
appears to be lower now than during those periods, uncovering 
the Tertiary border of the Southern States and leaving pre-glacial 
deposits with marine shells, apparently Post-pliocene, fifty to two 
hundred feet above our present sea-level, under the terminal 
moraine and modified drift of Long Island. The entirely unstrati- 
fied character which marks many portions of the terminal deposits 
of the ice-sheet, reaching quite to the sea-shore, and the still 
lower extension of the channels which appear to have been cut 
_ by the floods formed at its melting, indicate that at the south 
