164 Association of American Geologists and Naturalisis. 
action? Might there not have been a period when the northern portion 
of our hemisphere was covered with glaciers resembling those of the 
Alps, during which the furrows were produced by their gradual and 
radiolinear advance, followed by one of drifting ice, (whether borne 
along with a sudden rush of waters, caused by a paroxysmal elevation 
of land in the vicinity of the pole, or floods resulting from a gradual 
melting away of the mass, he would not now pause to inquire,) depos- 
iting bowlders through its course, and by the stranding and grinding of 
large masses into beds of sedimentary matter or drift, have occasioned 
the singular contortions visible in portions of the clay strata ? 
If it could be shown that a sudden and violent rush of waters from 
the polar region had taken place, sweeping over the whole northern 
portion of this hemisphere, bearing along with it large islands of ice, 
denuding the hills and filling the valleys with drift, and eventually sub- 
siding almost as rapidly as it poured southward,—would not this induce 
a belief that the remarkable, large bowl-shaped cavities described im 
k’s able memoir on the drift of New England, as existing 
on Cape Cod and elsewhere, might have been formed by the stranding 
and grinding of large islands of ice down: into the recently deposited 
drift? It occurred to Mr. C. at once; when these excavations were 
alluded to by Prof. Hitchcock, in connection with i ice,. that they might 
have originated in this manner, rather than from the of mat- 
ter round the melting ice, as suggested by that gentleman,—or they 
may haye been produced by a combination of these two operations; the 
grinding and settling down of the stranded berg, excavating a hollow, 
while the earthy materials contained in it would be piled up round the 
sides as it dissolved. If we supposed a very large berg of the pinma- 
cled character, to have been left aground by the subsidence of the 
paroxysmal flood, and divided into several smaller ones, each forming 
a separate crateriform bed for itself, we should then readily compre- 
hend the production of such a group of these cavities as was descri 
by Prof. H. Whether these suggestions were borne out by the: geolo- 
gical features of the drift in general, was left for those to determine 
whose observation had been more specially directed: os study of these 
phenomena. Mr. Couthouy of t! repeat that in 
relation to the production of diluvial, or to speak more aseial, gla- 
fur ; he. had: nospreeonevived. views of hiis own to-eupport, hat 
: fair ta taiis3 Svante tie fot poral 
