LTphain.] 
6 [Nov. 16, 
It Avould be expected that the abuiulance or absence of drum- 
lins must be determined, or at least influenced, by the varying 
contour and diversity in lithologic characters of the bed rocks ; 
but I have been unable to discover this relation or dependence, 
if any exists. In southern New Hampshire, and southward to 
the neighborhood of Boston, the druinlins are finely developed 
on some })ortions of the low land near the coast, being spread 
over areas which would otherwise be nearly level ; but at many 
places inland they are equally abundant among high irregular 
hills of rock. They seem as likely to be found on one side as 
another of any mountain or jn'ominent hill range ; and the alti- 
tudes at which they occur vary from the level of the sea to 1,500 
feet above it on the height of land between the Merrimack and 
Connecticut Rivers. Interspersed with the tracts of plentiful 
drumlins are other tracts which have none. If their distribution 
has been mainly independent of the differences in topography 
and the limits of various rock formations, as seems to be true, we 
are brought to the alternative that it probably resulted from 
movements of the ice-sheet and the conditions of its erosion, 
transportation, and deposition of the drift. 
Besides the frequent arrangement of these hills and ridges of 
till in groups and somewhat delinite belts, which are from a few 
miles to 10 or 20 miles wide, with intervening belts or irregular 
areas destitute of drumlins, a still more noteworthy feature of 
their geographic distribution is found in their occurring thus upon 
some extensive districts, Avhile they are utterly wanting on 
larger portions of the great glaciated areas of North America and 
Eui'ope. On this continent the districts where they are found 
range from southwestern New Brunswick through the southern 
parts of Maine and New Hampshire, and through Massachusetts 
and Connecticut, to central and western New York ; and farther 
toward the west, drumlins are encountered again in great abun- 
dance and variety in the eastern part of Wisconsin, extending 
also into the nortiiern peninsula of Michigan, beyond which they 
have been reported only as islands of Lake Winnipegosis in 
northwestern Manitoba. It seems very probable that all these 
areas were uncovered contemporaneously from the ice-sheet dur- 
ing the same general stage of its final recession, 
