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breadth and depth of the water, and is most, marked on the sides 
of the prevailing winds. It is, however, almost entirely 
wanting on the eastern ends of Thornbush and Telegraph Hills, 
Little Hog Island, Bumkin. Island, the western part of White 
Head and Hampton Hill, as well as the eastern shores of 
World's End and Planters’ Hill. At present, of course, these 
points are bordered by shallow water and, what is still more 
important, they are in the lee of Nantasket Beach, and are thus 
protected from the ceaseless beating of the ocean swell. It is 
perfectly clear, however, that this broad beach has been formed 
since the existing relations of the land and sea were finally 
established ; and if the postglacial elevation of the land had 
ceased when the present level was gained, the sea, sweeping 
freely through the broad passes between Strawberry Hill and 
Point Allerton on the north and White Head on the south, and 
the narrower gaps still further south, would inevitably have 
worn away the eastern ends of the masses of till which now 
enjoy the protection of the beach. Considerable and, at some 
points, ineffaceable results would undoubtedly have been accom- 
plished before the sea sueceeded in throwing up the barrier 
beach that now checks its own depredations. The absence of 
sensible erosion at these points is, however, readily explained, 
if we admit that the comparatively rapid elevation of the land 
probably continued until it stood somewhat higher than at 
present ; and that a slow and gradual subsidence has since been 
in progress. Whenever, during this subsidence, the depres- 
sions between the drumlins of what is now the Nantasket 
Peninsula were brought within reach of the waves, barrier 
beaches were naturally formed across them ; and these barriers 
have kept pace in their upward growth with the subsidence, so 
that the land behind Nantasket Beach has been continuously 
protected from the action of the surf. This view relieves us of 
the necessity of imagining a cordon of drumlins outside of the 
present beach which have been completely washed away, 
although. it is not improbable that Harding's Ledge and. the 
