W. M. Davis—Distribution of Drumlins. 409 
TERMINOLOGY.—Drumlin ; M. H. Close, Notes on the gen- 
eral glaciation of Ireland; read in 1866; Journ. Roy. Geol. Soe. 
Ireland, i, 207. A word of Irish derivation, meaning a long 
rounded hill. Most of the following terms are essentially 
synonymous with it, although some have a more specific mean- 
ing, 
Parallel ridges; Sir James Hall, Trans. Roy. Soc. Edinb., 
1815, vii, 169. 
Drums and Sow-backs of Scotland; J. Geikie, Great Ice Age, 
1877, 13, 76. 
Parallel ridges; N.S. Shaler, Proc. Bost. Soc. Nat. Hist., 
4840, x1, 37. 
Lenticular hills; C. H. Hitchcock, id., 1876, xix, 68. These 
als papers refer to hills of more oval form than those of Ire- 
and. 
Whalebacks in New Brunswick; G. F. Matthew, Geol. Sur- 
vey Canada, 1877-78, 12EE. These are not clearly separated 
from hills of stratified gravel. 
vets drift-hilis ; L2Johnson, Trans. N. Y. Acad. Sei., i, 
82 
Mammillary or Ellipticai hills; T. C. Chamberlin, Geol. Wis- 
gona, 1883, i, 283. Some of these have an almost circular 
ase. 
Of these several terms, drumlin appears by far the best in 
being a name, not a description; in having in English at least 
no other meaning than the technical one here adopted ; and in 
having been proposed .by the author who first gave a sufficient 
clue to the origin of these hills. It does not seem worth while 
to coin a word, as botanists and zodlogists are forced to do, for 
already a number of local names from various languages have 
Come into general use in geography, as pampa, selva, steppe, 
tundra, atoll, delta, mesa, cafion, moraine; and drumlin may be 
well added to the list. Drumlins, using the term in its general 
sense, may be specifically qualified as long, oval or round. 
General description —Drumlins are hills composed of com- 
pact, unstratified glacial drift or till; their form is usually 
elongate or oval, with a ratio of horizontal axes varying from 
6:1 to 1:1; the longer axis is parallel to former local glacial 
Motion, as shown by neighboring striation or plied ype of 
bowlders; the profile is generally smoothly arched and com- 
monly almost symmetrical; terminal slopes, 3° to 10°; lateral 
Slopes, 10° to 20°; length, one-eighth to two or more miles; 
height, 20 to 250 feet above base. The general uniformity of 
Outline in any single region is very noticeable; indeed the 
View from the summit of a commanding drumlin, in the center _ 
of a group, shows as characteristic a landscape as that seen in 
looking from the Puy de Déme over the extinct volcanoes of 
