Upham.] 
130 
[Dec. 19, 
been the subject of several papers before this Society. 1 Approx- 
imate elevations of the drumlins in which fossils have been found 
are as follows : Grover’s cliff, 60 feet above the sea ; Great Head, 
100 feet; Eagle hill, East Boston, 120 feet; north end of Long 
island, 75 feet; George’s island, 60 feet; Moon island, 100 feet; 
north end of Peddock’s island, 70 feet ; Nut island, 40 feet ; Quincy 
Great hill, 100 feet; on the north shore of Hull, 80 feet; Tele- 
graph hill, 125 feet; and Sagamore Head, 65 feet. The cliffs 
eroded by the sea on most of these drumlins extend from ten or 
fifteen feet above mean tide sea level upward very steeply or of- 
ten in part vertically to near their tops. 
Excepting Great Head, which contains modified drift near its 
base, to be presently described, these sections consist wholly of till 
or boulder-clay, the direct deposit of the ice-sheet, unmodified by 
the transporting and assorting action of water. Weathering has 
changed the small ingredient of iron in this deposit from the pro- 
toxide combinations which it still retains in the lower part of the 
till to the hydrous sesquioxide in its upper part for a depth of com- 
monly fifteen or twenty feet from the surface, thereby giving to the 
latter a yellowish color in contrast with the darker gray or bluish 
color of the former. Both portions are very compact and hard till, 
an intimate unstratified commingling of boulders, gravel, sand and 
clay, and seem by these characters, and by their abundant striated 
boulders and smaller fragments of stone, to be distinctly the ground 
moraine of the ice-sheet. The southeast and east-southeast trends 
of the longer axes of the drumlins in this vicinity, coinciding at 
least approximately with the direction of the striation of the bed- 
rock, further indicate that these oval hills of till were accumulated 
beneath the ice-sheet, this form being that which would oppose the 
least resistance to the glacial current passing over them. Though 
the till is destitute of stratification, its materials, coarse and fine, 
from boulders often several feet and occasionally ten feet or more 
in diameter to the finest rock-flour, being indiscriminately mixed 
in the same mass, it yet generally shows an obscure lamination in 
*By Prof. N. S. Shaler, Pi-oceedings, vol. xiii, pp. 198-203; byPi-of. C. H. Hitchcock, 
vol. xix,pp. 63-67; and by the present winter, vol. xx, pp. 220-234. Also, see Geology 
of New Hampshii-e, vol. iii, pp. 285-309; “The Distribution and Oi*igin of Drumlins,” 
by W. M. Davis, in Am. Joui’n. Sci., in, vol. xxviii, pp. 407-416, Dec., 1884; and Illus- 
trations of the Earth’s Surface: Glaciers, by Professoi-s Shaler and Davis, plate xxiv. 
