552 The Formation of Cape Cod. [September, 
THE FORMATION OF CAPE COD. 
BY WARREN UPHAM. 
[Continued from August Number] 
N Cape Cod, as on Long Island, Martha’s Vineyard and Nan- 
tucket, we find, south of the line of morainic hills, an area of 
modified drift in extensive plains which slope very gently south- 
ward. These are fully ten miles wide from north to south in 
Sandwich, Falmouth and Mashpee, and thence to the east they 
have an average width of five miles. From the south-west limit 
of this area at Falmouth village, the traveler who follows the 
road along the south side of the cape through Waquoit, Cotuit, 
Hyannis and the south villages of Yarmouth, Dennis and Har- 
wich, sees only level plains twenty-five to forty feet above the sea, 
with occasional hollows and valleys, most of which are occupied 
by ponds and brooks. No boulders are seen in this distance of 
more than thirty miles. They occur, however, in the small hills 
west of Hyannis harbor, the highest of which is eighty-one feet 
above the sea, and in lower mounds and ridges two and a half 
miles south-east at Point Gammon. Shoals of boulders, known 
as Collier's Ledge and the Bishop and Clerks, lie three miles off 
shore opposite to these points. Chatham and Orleans, at the east 
end of this area, are also modified drift, but its surface is very 
irregularly moulded into hills, ridges and enclosed hollows, the 
highest elevations being about one hundred and twenty-five feet 
above the sea. The north edge of this area, next to the terminal 
moraine, consists of more elevated plateaus, fifty or seventy-five 
to two-hundred feet in height. From this line there is a con- 
tinuous slope southward, scarcely perceptible but declining in the 
five to ten miles of its extent to within twenty-five to forty feet 
above the sea. This north portion of the plains is marked by 
frequent hollows of large extent, which contain ponds fifty to one 
hundred feet below the general surface. : 
A fine idea of the slope of this deposit of modified drift 1s 
obtained in a journey from Sandwich to Greenville, Ashunet pond 
and Falmouth. -The ascent of two hundred feet or more from 
sea-level to the highest point of the road is accomplished. in two 
miles, bringing us to a point on the road where Bourne’s hill, the 
highest on Cape Cod, is within a half mile to the east, while close 
-~ at the west is the Great Hollow, about one hundred feet deep and 
