Glacial Geology in America. — Fairchild. 173 
Chamberlin in 1883 called them "mammillary" or "elliptical 
hills." The name drumlin was proposed for use in this coun- 
try by W. M. Davis, in 1884, and at once adopted. 
As nearly all drumlins are composed wholly of till, and 
especially so in the superficial part, it w^as early recognized 
that they were an immediate product of ice work, and they 
were so referred by Close as early as 1864. In 1872 Kinahan 
and Close regarded them as subglacial and constructive, com- 
paring them to the longitudinal sand-bars in the bed of a 
stream. This view of the genesis of drumlins has been 
adopted, in a general way, by most American glacialists. 
The suggestion, made by professor Shaler in 1870, that they 
may be remnants of an earlier, eroded drift sheet, or that they 
represent old moraines remodelled by readvance of ice, as pro- 
posed by C. H. Hitchcock, have been quite abandoned. Their 
parallelism wdth the direction of ice movement was first noted 
in America by Hitchcock and Upham in 1875. I" 1883 pro- 
fessor Chamberlin discriminated drumlins from moraines, as 
being longitudinal, or axi-radiant with reference to the mov- 
ing ice body. 
The hypothesis of drumlin origin by the piling of the 
ground-moraine by differential pressure and movement of the 
overriding ice body, along the peripheral zone where trans- 
porting power becomes inadequate to the drift burden, is re- 
garded as a plausible and satisfactory explanation. The chief 
objection to this is negative, the failure of more uniform dis- 
tribution and even the entire absence of drumlins over vast 
areas of drift. Another difficulty is physical ; a lack of precise 
knowledge of the manner in which ground moraine is lifted 
in relatively short distances to heights of 100 or 200 feet. Mr. 
Upham has attempted to solve this problem by an argument 
for the construction of drumlins, and moraines also, by the 
lodgment of englacial drift. This difficulty is less acute, 
however, since professor Chamberlin had observed sections 
of miniature drumlins beneath the ice foot of the Greenland 
glaciers, with the overriding ice moulding itself to the drum- 
linoid curve. 
Moraines. — The masses of moraine drift were not entirely 
overlooked in early writings upon the diluvial phenomena, yet 
they were not emphasized since their superior importance and 
