156 The American Geologist. Soptembor, i898 
chison gives to this letter of Dobson the credit of suggesting 
to him the iceberg hypothesis, while Edward Hitchcock ob- 
tained his similar idea from Sir James Hall of Scotland. 
So far as the writer has discovered in print no American 
geologist suggested land or glacier ice as a possible cause of 
the drift phenomena until 18.^7. when T. A. Conrad asserted 
his belief in such agency in the following words: 
"Whence then this immense body of ice which has scattered boulders 
over so vast a tract of country, appearing too at an epoch subsequent 
to the extinction of the Mastodon and other mammalia, which evi- 
dently lived in this region and enjoyed equatorial climate anterior to 
the icy period? Nothing can reconcile this apparent contradiction 
but the admission of a fall of temperature far below that which prevails 
in our day, freezing the enormous lakes of that period and converting 
them into immense glaciers, which probably continued undiminished 
during a long series of years." 
We cannot, however, regard Conrad's suggestion as a fair 
presentation of the glacial theory. It was made only incident- 
ally, as an argument for his hypothesis of epochs of cold cli- 
mate, and without any attempt to give a full statement or to 
marshall the facts as bearing upon the genesis of the drift. It 
is significant, however, as indicating, by the casual way in 
which he introduces the argument, that the conception of 
great bodies of land ice might not have been, even at that time, 
an entirely new idea to American geologists. The work which 
then had been prosecuted for some years upon the alpine gla- 
ciers was probably not entirely unnoticed by Americans. 
The American geologist who first gave a favorable recep- 
tion to the glacial theory of Agassiz, as far as printed records 
show, was Edward Hitchcock. In his address as retiring pres- 
ident at the second annual meeting of the Association of 
American Geologists and Naturalists, held at Philadelphia, 
April, 1841, he described the characters of the drift and the 
various phenomena which we now call glacial with great ac- 
curacy and appreciation. After discussing several hypotheses 
of the drift he writes as follows : 
"But the recent work of Agassiz, entitled 'Etudes sur les Glaciers,' 
gives a new aspect to the subject Henceforth, however, 
glacial action must form an important chapter in geology. While 
reading this work and the abstracts of some papers by Agassiz, Buck- 
land and Lyell, on the evidence of ancient glaciers in Scotland and 
