_» © Erratic Phenomena about Lake Superior. 98 
- such extensive phenomena than they are now. That is to say, 
_*We must assume an ice period; and if we look into the circum- 
_ Stances we shall find that this ice period, to answer to the phe- 
~homena, should be nothing less than an extensive cap of ice upon 
both poles. This is the very theory which I advocate; and un- 
less the advocates of an iceberg theory go to that length in their 
premises, I venture to say, without fear of contradiction, that 
site conditions which they must assume, upon due consideration, 
_¢to account for the whole phenomena as they have really been 
observed. 
_ But without discussing any farther the theoretical views of the 
question, let me describe more minutely the facts as observed on 
the northern shores of Lake Superior. 'The polished surfaces, 
as such, are even, undulating, and terminate always above the 
rough lee-side turned to the south, unless upon gentle declivities, 
where the polished surfaces extend in unbroken continuity upon 
the southern surfaces of the hills, as well as upon their northern 
slopes. On their eastern and western flanks, shallow valleys run- 
--Horth and south; and this fact is more and more evident, wher- 
seen everywhere in those narrow inlets, with shallow waters in- 
tersecting the innumerable highlands along the northern shores 
of Lake Superior, where the scratches and furrows can 
under water from one shore to the other, and where they at times 
ascend steep hills, which they cross at right angles along their 
Northern slope, even when the southern slope, not steeper in it- 
self, faces the south with rough escarpments. 
e scratches and furrows, though generally running north 
and south, and deviating slightly to the east and west, present in 
Various places remarkable anomalies, even in their general course 
Ong the eastern shore of the lake. Between Michipicotin and 
Sault St. Marie we more frequently see a deflection to the west 
than a due north and south course, which is rather normal along 
the northern shore proper, between Michipicotin and other isl- 
» and from the Pic to Fort William; the deep depression of 
the lake being no doubt the cause of such a deviation, as large 
Masses of ice could accumulate in this extensive hollow cavity 
k 
they will find the source of their icebergs fall short of the requi- ~ 
