252 Address before the Association of American Geologists. 



Yet eleventhly, this agency must have been comparatively 

 recent. For the disintegration of the surface of the smoothed 

 and furrowed rocks to the depth of half an inch, would usually 

 obliterate all traces of their erosion. Yet in how many places 

 does this effect appear as distinct as if produced during the pres- 

 ent century! 



Finally, this agency must have been far more powerful than 

 any now operating upon the globe. In the language of Prof. 

 John Phillips, which he applies to the phenomena of drift in 

 general, " such effects are not at this day in progress, nor can we 

 conceive the possibility of their being produced by the operation 

 of existing agencies operating with their present intensities and 

 in their present directions." — Treatise on Geology, Vol. 1, p. 

 296. 



Beyond such independent inferences as these, I confess I have 

 been of late years unwilling to go ; and have regarded the nu- 

 merous theories of diluvial action, which have recently appeared, 

 only as ingenious hypotheses. But it is well known that the 

 Glacier Theory, originally suggested by M. Venetz, and subse- 

 quently adopted by M. Charpentier, and more fully developed of 

 late by Agassiz, is now exciting great interest in Europe. To 

 say nothing of geologists in this country who have expressed 

 themselves favorably towards it ;* it is surely enough to recom- 

 mend it to a careful examination, to learn that such men as Agas- 

 siz, Buckland, Lyell and Murchison, after long examination, have 

 more or less fully adopted it; although on the other hand, it ought 

 to be mentioned, that such geologists as Beaumont, Sedgwick, 

 Whewell, Mantell, and others, still hesitate to receive it. 



In a country like ours, where no glaciers exist except in very 

 high latitudes, and with the very defective accounts which have 

 hitherto been given of those in the Alps, it is not strange that the 

 attempt to explain the vast phenomena of diluvial action by 

 such an agency, should appear at first view, fanciful, and even 

 puerile. But the recent work of Agassiz, entitled Etudes sur les 

 Glaciers, gives a new aspect to the subject. It is the result of 

 observations made during five summers in the Alps, especially 

 upon the glaciers ; about which so much has been said, but con- 



* See ^Jl•. Conrad's Notes on American Geology, in Am. Journal of Science, 

 Vol. XXXV, p. 237. 



