of the North American Ice-Sheet. 205 
stones, exposed for twenty feet vertically but concealed below. 
e bed of bowlders which forms the shore at this point came 
mostly from the upper stratum, and their sharp corners and 
ges have since been worn away by the waves. 
On Cape Cod, as on Long Island, Martha’s Vineyard and 
Nantucket, we find south of the line of morainic hills an area 
of stratified gravel and sand without bowlders, forming exten- 
sive plains which slope very gently southward. These are 
fully ten miles wide from north to south in Sandwich, Fal- 
mouth and Mashpee, and thence to the east they have an aver- 
age width of five miles. From the southwest limit of this 
area at Falmouth village, the traveler who follows the road 
along the south side of the cape for thirty miles sees only level 
— twenty-five to forty feet above the sea, with occasional 
ollows and valleys, most of which are occupied by ponds and 
brooks. The north edge of this area, next to the terminal 
moraine, consists of more elevated plateaus, 50 or 75 to 200 
feet in height. From this line there is a continuous slope 
southward, scarcely perceptible, but declining in the five to ten 
miles of its extent to within twenty-five to forty feet above sea. 
This north portion of the plains is marked by frequent hollows 
of large extent, which contain ponds 50 to 100 feet below the 
general surface. A fine idea of the slope of this deposit of 
modified drift is obtained in a journey from Sandwich to Green- 
ville, Ashunet Pond and Falmouth. " The ascent of 200 feet or 
Point it crosses numerous depressions that are or have been 
water-courses; but there is no break in the continuity of the 
plains, which in about twelve miles descend by a gradual slope 
from the height of 200 feet to sea-level. ; 
These plains of Cape Cod are also like those previously 
described in being indented by narrow arms of the sea whi h 
Teach one to two miles inland, filling the lower end of long 
depressions that continue across the plains to the north, being 
either dry or occupied by small streams. These channels are 
best shown on Cape Cod in Falmouth and eastward to Cotuit 
t, being in the’ region directly south from the angle of 
the terminal moraine and from its highest hills, which in this 
Portion of its course are composed mainly of modified drift ; 
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