Perry.] 5 8 [February 28, 
§ 1. The Indications of Ice-A gency, 
Or the facts suggestive of the extensive presence of moving ice in 
New England, require an accurate enumeration in order to their 
critical and careful study. While the glacial hypothesis is admitted 
and defended by Professor Dana, he does not profess, as it was not 
needful for him, to give in his paper a formal presentation of the evi- 
dence respecting the point suggested. As the question whether this 
recion were once subjected to the agency of ice, be it in the shape 
of icebergs, of glaciers, or in any other form, is one of importance, 
it will be well, perhaps, to cite several of the more weighty consider- 
ations supposed to point in that direction. ‘These may be conveni- 
ently classed under three heads, accordingly as they pertain almost 
universally to the underlying solid rocks, or very generally to the 
superimposed loose material, or finally, to certain results which are 
only occasional in their appearance. 
A. Indications from Underlying Rock-Masses. 
1.) The erosion of the subjacent rocks. This is clearly manifest 
from exposed surfaces which may be seen, here and there, all over 
New England. In some way or other vast amounts of matier have 
been certainly worn off, and removed from nearly, if not from quite 
all the earlier surface of the country. A slight examination shows 
that the work wrought by denudation has been immense. And this 
was of a peculiar kind, not from ordinary atmospheric influences, 
and not from flowing water; there was apparently a stupendous 
agency, as it were a huge machine, acting like a gouge, or working in 
a rasp-like way on the entire surface of the rocks. In connection 
with this agency lake-beds were evidently deepened, perhaps in 
some instances formed outright, their rocky shores in places lately 
laid bare affording marks, as of an immense plane, passing down- 
ward into their basins at an angle varying from a slight inclination to 
seventy or eighty degrees. So river-channels, at a comparatively 
recent day, have been as clearly made wider and deeper; in given 
localities they have been manifestly scooped out and broadened by 
this wondrous instrumentality ; while the remaining vestiges of the 
operation evince, beyond reasonable question, that the result was 
not effected by water in its usual mode of working. All this is evi- 
dent from the various indications found here and there on the rocks 
that form their sides, and the flanks of the valleys which they 
