“ aaa hae’ = ‘ ; rae . 
- / 
. : Fl 
i , 
* 
> Erratic Phenomena about Lake Superior. a 
in:their arrangement they present everywhere the most striking 
--@ontrast when compared with deposits: accumulated ‘under the 
agency of water. Indeed, we nowhere find this glacial drift reg- 
ularly stratified, being everywhere irregular accumulations of ~- - 
loose materials, scattered at random without selection, the eears- “ 
est and most minute particles being piled irregularly in larger or 
smaller heaps, the greatest boulders standing sometimes upper- 
most, or in the centre, or in any position among smallér pebbles 
- , and impalpable powder. Oo 
_ «) And these materials themselves are scratched, pglished and fur- 
~ rowed, and the scratches and furrows are rectilinear as upon the 
rocks tn situ underneath, not bruised simply, as the loose materi- 
_als carried onward by currents or driven against the shores by 
the tides, but regularly scratched, as fragments of hard materials 
would be if they had been fastened during their friction against 
each other, just as we observe them upon the lower surface of 
glaciers where all the loose materials set in ice, as stones in their 
setting, are pressed and rubbed against underlying rocks. But 
the setting here being simply ice, these loose materials, fast at one 
time’and movable another, and fixed and loosened again, have 
Tubbed against the rock below in all possible positions ; and hence 
not only their rounded form, but also their rectilinear grooving. 
How such grooves could be produced under the action of cur- 
rents, I leave to the advocates of such a theory to show, as soon 
as they shall be prepared for it. te 
I should not omit here to mention a fact which, in my opinion, 
has a great theoretical importance, namely, that im the northern 
erratics, even the largest boulders, as far as I know, are rounded, 
and scratched and polished, at least, all those which are found 
beyond the immediate vicinity of the higher mountain ranges; 
showing that the accumulations of ice which moved the northern 
_ €rratics covered the whole country; and this view is sustained 
by another set of facts equally important, namely, that the high- 
est ridges, the highest rugged mountains, at least, in this conti- 
nent and north of the Alps in Europe, are as completely polished 
and smoothed as the lower lands, and only a very few peaks seem 
to have risen above the sheet of ice; whilst, in the Alps, the 
