82 The America?i Geologist. Aagust, i89y 
From this point of view we see all New England, Long 
Island, and the country westward, raised in early Pleistocene 
time about 3,000 feet higher than now, with rivers, as mapped 
by Shaler, flowing east and northeast from Massachusetts bay 
and Cape Cod bay, another river flowing east between Cape 
Cod and Nantucket, another running southward between Nan- 
tucket and Martha's Vineyard, and others southwestward from 
Vineyard sound and Buzzard's bay. When the land attained 
its maximum elevation, a sheet of ice, fed by the snowfall, over- 
spread the northern half of the continent, excepting Alaska, 
and reached to an extreme southern limit nearly represented, 
in its eastern part, by the outer terminal moraine of Long Isl- 
and, Block island, Martha's Vineyard, and Nantucket. Far- 
ther east, I believe that the ice-sheet stretched at one time to 
the Fishing banks, including George's bank, the Western or 
Sable Island bank, and the Grand bank of Newfoundland, al- 
though inside that boundary the area of the Gulf of St. Law- 
rence had a driftless, unglaciated tract, partly known to us in 
the Magdalen islands, while also probably the area now occu- 
pied by the Gulf of Maine was the site of a deeply reentrant 
angle or sinus of the ice border, between its George's Bank 
and Nova Scotia lobes. The ice in these latitudes nowhere 
reached to the sea level during the period of continental uplift. 
About 3,000 feet below the ice boundary, along the coast as it 
then was, most of the plant species of our temperate region 
may have survived and flourished, ready to spread northward 
again over their former realm as soon as the subsidence of the 
continent restored there a temperate climate. The return of 
the flora kept pace closely with the departure of the ice; and 
thus I think that these islands, as they came to be at the close 
of the Ice age, received their trees and other plants chiefly 
from the former lands adjoining them which then were gradual- 
ly submerged. 
It was after the end of the Tertiary era when this region 
was uplifted to produce the Hudson submarine channel and 
cafion, and to cause the accumulation of this part of the ice- 
sheet; "for we have preglacial fossiliferous deposits on Gardin- 
er's island, adjoining the east end of Long Island, and in the 
sea cliflf of Sankaty head on Nantucket, including many spe- 
cies, all of which are still living. Likewise, in Massachusetts 
