241 
LUpham. 
extent, and that consequently the rate of motion of the outer part 
of the ice-sheet was even increased during its final melting. This 
would still further explain the exceptional rates of both erosion and 
deposition that are indicated by the shell fragments contained in 
the till of some of these drumlins from base to crest, as on Ped- 
dock’s Island, where also the dark bands showing stages of growth 
are very distinct. 
Another indication of the late formation of the drumlins is found 
in the relationship of Third Cliff and Coleman’s Hill in Scituate. 
A half mile west from the eroded sea-cliff of this drumlin is the 
east end of a notable kame or esker called Coleman’s Hill, which- 
extends about a mile, trending nearly due west, and terminating at 
Greenbush station (see fig. 1). It is a stratified deposit of sand 
and fine and coarse gravel, containing cobbles up to one foot in di- 
ameter, mostly somewhat rounded by water-wearing, but destitute 
of boulders. The top of this esker is flat upon a width that varies 
from two or three to ten or fifteen rods ; and its height is 110 to 
100 feet above the sea, declining slightly in its length of one mile 
from east to west. Its sides are steep, and the width across its base' 
varies from a sixth to a third of a mile. On the south it is bordered by 
a broad salt-marsh, through which a creek meanders in a beautifully 
curved course ; and on the north the adjoining low land is from ten- 
to twenty feet above the sea. This esker was undoubtedly deposited 
by a stream that descended here, flowing east, from the surface of 
the melting and receding ice-sheet, laying down its coarse sedi- 
ments in a broad channel bordered on each side by ice. Its origin 
was like that of the series of osars in Maine, in the Merrimack and 
Connecticut valleys, and in Sweden ; or perhaps we might better 
say that it is intermediate in origin and character between these 
prolonged, narrow gravel ridges and the broad deposit of modified 
drift which forms the fore-arm of Cape Cod, north of Orleans. The 
structure of the till-covered hill of Third Cliff, and its topographic 
position in the same east to west line with Coleman’s Hill, convince 
me that the two were formed in close succession during the retreat 
of the ice-sheet at the end of the latest glaciation of this area. 
If the dark bands noted in the till of Third Cliff, Peddock’s Isl- 
and, and elsewhere, are marks of accumulation in successive years, 
which seems highly probable, the drumlins of Boston and vicinity 
PROCEEDINGS B. S. N. H. VOL. XXIV. 16 SEPTEMBER, 1889. 
