Address before the Association of American Geologists. 251 
_Eighthly, water must have been one of the forces employed 
in this agency. The regular deposits of clay and sand which 
form the upper part of the diluvial deposit, must surely have 
been accumulated at the bottom of bodies of water, which have 
subsequently been drained off. Much, also, of the fiver part of 
our drift is more or less stratified, and exhibits that oblique lamin- 
ation which is peculiar to aqueous deposits. Nor can I conceive 
of any other mode in which detritus has been transported hun- 
dreds of miles, as ours has been, but by the aid of water; al- - 
though this alone could not do it. In New England, we have 
been able to trace erratic blocks not more than one hundred or 
two hundred miles, because we then reach the ocean. But in 
the central parts of the country, I am informed by Prof. Mather, 
that the primary bowlders from Canada and the western part of 
Michigan, are found.as far south as the river Ohio ; which would 
en their‘maximum, transit from four ‘hundred. “ five hundred 
ye 
have been carried into Gi _ What agency tien pies eval 
ve ected ach a nsjoration? ha HE reed Net 
It is very natural, also, to doa einen: 
ing of the rocks to the action of water. raps in vain ex- 
amined the beds of our mountain torrents and the shores of the 
Atlantic, where the rocks have been exposed to the 
and everlasting concussion of the breakers, and can find nome 
trition that will compare at all with that connected with drift ; 
and I am eapaenetes n- qe it we ii RAR ae 
agency. 
Ninuily,4 ice must have baits sath pees biniiged: to pro- 
duce the phenomena of drift. What else could have transported 
large blocks and gravel over such a wide space as has been men- 
tioned, and have lodged them ee —_— the a oe — one 
ipitous ridges; and especially, what o agent cou 
samen those singular mounds and:petuliar ridges'of ‘gravel and 
bowlders that meet us in so many places? 
-Tenthly, thisagency must have been exerted mater = to the 
existence of man. upon this continent, and have been of such a 
nature as to destroy organic life almost entirely. » For the remains 
of —— nna other existing. animals have. not been found 3 in pete! 
sega and sand a aren a 
Scarcely contain a species of animal or plant. 
