Great Lake Basins of the St. Lawrence. O71 
when we consider the extensive areas crossed by the glacier 
between the lake and the moraines, and the vast Laurentian 
and Huronian country to the northward, then more or less 
glacier-clad and supplying debris, apart from the accumu- 
lated debris of ages previous to this time. Prof. Claypole 
has encountered the same difficulty in discussing the so- 
called moraines to the south of Lake Hrie. 
The character of the floor of the northern half of the lake 
also presents difficulties. The direction of the old river 
channels and of the depressions, varying from east and west 
to north and south, the frequent abruptness of the descent 
to them, the directions of the axes of the promontories and 
neighbouring islands, and the absence of any general filling 
up of the hollows and depressions of the lake bottom in its 
northern half, all indicate that the glacier, if it existed, did 
not contribute to the forming of many of the leading out- 
Imes of the coast, or to the stamping of the chief features 
upon the lake floor. The subject will, however, be further 
discussed when referring to Lake Ontario in connection with 
this lake and Lake Huron. 
LAKE ONTARIO. 
An important fact which at once strikes the observer, 
when noting the soundings in this lake, is that the areas 
of greatest depth are all towards the southern side of the 
lake. The deepest point is 738 feet or 506 feet below the 
ocean level, and is located about fifteen miles off the New 
York State side, between Rochester and Oswego. The 600- 
foot line here encloses an area of about thirty-eight miles 
long and ten miles broad, lying about parallel to the coast, 
and within eight miles of it. ‘To this deep depression there 
is a fall of about 300 feet in two and a-half miles on its im- 
mediate southern side. On the northern side the descent 
is more gradual, Another depression exceeding 600 feet, 
but very small in area, exists about the seventy eighth 
meridian of longitude, but similarily towards the United 
States side. Again, the 300-foot line encloses an area about 
