206 W. Upham—Terminal Moraines - 
in other words, they occur most abundantly where the drainage 
from the melting ice-sheet must have been greatest, including 
all the floods poured down from the ice-fields along the line | 
' between Falmouth village and North Sandwich, those that con- 
verged toward the angle of the ice-margin, and those which 
brought down its vast frontal hills of gravel and sand along 
several miles eastward. 
Extensive portions of the terminal moraines were deposited, 
as we have seen, by rivers which flowed from the su co} 
the melting ice when a warmer climate returned. On the south 
side of these the plains have their greatest width and height, 
while on the north we also find extended areas of modi 
drift, which show that the glacial floods continued to be poured 
down to the same portions of the ice-margin during its retreat. 
Thus on Long Island the area north of the extensive moraine 
from the Narrows to Roslyn consists almost wholly of undulat- 
ing unmodified drift with abundant bowlders, while farther 
eastward it is stratified gravel and sand with few bowlders. 
Wherever angles occurred in the terminal front of the ice its 
surface had converging slopes, which would be likely to pro- 
duce extraordinary fluvial deposits. This may explain the 
origin of the thick beds of stratified drift which form nearly 
the whole of Block Island, and of the plains in South Kings- 
town, R. I, which extend six miles north from the angle of the 
second moraine, reaching from Tucker's and Worden’s Ponds 
to the north line of the township. The plains south of the 
moraines at their angles near Vineyard Haven and North Sand- 
wich are notably due to the debouchure of glacial rivers at 
these points; and when the ice-sheet retreated from its second 
moraine, the floods which it discharged formed a most irregu- 
lar belt of gravel and sand in ridges, hills, plateaus and hol- 
lows of every shape, but generally with a north-to-south trend, 
through a distance of nearly twenty miles to the north and 
north-northwest, reaching from its angle at North Sandwich 
through Plymouth to Kingston. West and north from these 
kames, the greater part of Plymouth County consists of nearly 
level or moderately undulating deposits of modified drift, 50 to 
_ 150 feet above sea, which reach continuously from the angle of 
the terminal moraine on Cape Cod more than thirty-five miles 
to Hingham, on the south shore of Massachusetts Bay. Another 
and perhaps more remarkable series of fluvial deposits was SUp- 
plied from the melting ice-sheet to form Nantucket, the hills 
which rise 75 to 125 feet above sea in Chatham, the southeast 
townsbip of Cape Cod, and the north portion of this peninsula 
beyond Orleans, which consists entirely of modified drift from 
50 to 175 feet above sea. 
‘The first recognition of the terminal moraines of southeastern 
