1 62 TJie American Geologist. September, isyi> 
■'V. The diluvial hypothesis, as modified by myself, assumes, not 
liie submersion of the land but a series of violent elevatory earthquake 
movements, in the arctic regions, displacing the arctic waters, with 
the ice which bound them, and sending these southward, across the 
northern districts of the continents." 
As early as 1842 the facts concerning the geologic work 
of the Alpine glaciers and the argimients for the glacial theory 
had been placed before American readers by the republication 
in Silliman's Journal of an excellent article by Charles Mac- 
laren. And in the next year of an elaborate review in the same 
journal, of James Forbes' noble book on glaciers left American 
geologists with no excuse for lack of general knowledge of 
the glacial theory and its reasonable claims. 
Late in 1846 Louis Agassiz arrived in America. In 1847 
he explored the White Mountains and found evidence of local 
glaciers. In 1848 he visited the great lakes and found abun- 
dant evidence of continental glaciation. In September of that 
year he attended the first meeting of this society, at Philadel- 
phia, and described the glacial phenomena about lake Super- 
ior, showing the identity of the phenomena in America with 
those in Europe. To his personal testimony was added that 
of Arnold Guyot and Edmund Desor, who had been colab- 
orers with him and had also brought their ample experience 
to bear upon the American field. The reception by the older 
geologists of this personal and expert evidence was evidently 
not of such a character as to encourage Agassiz in further pre- 
sentation of the matter. In his book on lake Superior, pub- 
lished 1850, he wrote in a somewhat sarcastic vein as follows: 
"But such is the prejudice of many geologists that those keen 
faculties of distinction and generalization, that power of superior per- 
ception and discrimination, which have led them to make such brilliant 
discoveries in geology in general, seem to abandon them at once as 
soon as they look at the erratics." 
Agassiz did not present another glacial paper before the 
Association until 1870, his chief work in the meantime lying 
in the domain of zoology. However, from about 1850 the ex- 
treme diluvial notions were either abandoned or presented 
less agressively. 
At the second meeting of this Association, in Caml^ridge, 
1849, there was the usual animated discussion of the drift, fol- 
lowing papers by H. D. Rogers and Arnold Guyot. An ex- 
