The Madison Type of Drumlins. — Upham. 71 
are nearly 700; and Mr. George H. Barton, mapping them in 
Massachusetts, under t lie direction of Prof. N. S. Shaler. for 
the United States Geological Survey, finds about 1,500 drum- 
lins. counting, as in New Hampshire, the separate rounded 
summits of compound drumlin aggregations, where two or 
three of these hills, and sometimes more, are merged together 
at their bases. 
Nearly all of the many sections of drumlins shown in the 
vicinity of Boston by artificial excavations, and more exten- 
sively by the high cliffs where these hills are being worn away 
and freshly undermined by the sea, reveal only till, very com- 
pact and containing frequent or plentiful boulders up to five 
feet or rarely ten feet in diameter, which, like the smaller 
embedded stones and pebbles, usually have glaciated forms 
and often preserve distinct glacial stria\ This deposit is the 
direct product of the ice-sheet. Any traces of assortment or 
stratification by water are exceedingly rare. Instead, the till 
derived from glacial transportation and deposition is seen in 
numerous sections to extend quite from the base of these hills, 
or from the sea level, upward through their central part to 
their crests. The compactness of the till, its abundant gla- 
ciated stones, the peculiar lamination of its clayey matrix, 
due to the gradual surface accretion, and other characteristic- 
features, clearly demonstrate it to he an accumulation formed 
beneath the weight of tin- overriding ice-sheet, whose current 
moulded the growing drumlins in their smooth oval forms, 
having their longer axes parallel with the latest movement of 
the ice over them. Only a small amount of finally englacial 
drift, apparently averaging no more than from one to three 
feet in the neighborhood of Boston, was dropped on these 
hills from the ice-sheet when its waning border retreated past 
them. 
After studying the drumlins of New Hampshire and eastern 
.Massachusetts more than ten years, I first learned of the ob- 
servation of an instance with a nucleal stratified deposit by 
Mr. Dodge's description of the sea-cliff section of Greal Head, 
which rises by a steep newly undermined -lope, and near the 
top vertically, to a (light of LOO feet above the ocean. This 
section consists of ordinary till, weathered yellowish above 
but dark bluish below, from its top to within "Jo or 1 "> feet 
