REVIEW OF GEOLOGICAL STRUCTURE. 4q 
traversed by an old river channel, which is very much deeper than most 
of the lake itself, it is incomprehensible that it should not have been 
cut as deeply by the old river as Lake Huron was, since the rocks to be 
removed were the same. 
Lake Ontario is again a deep basin, being 450 feet deep with a surface 
level of only 234 feet above the ocean.* Every thing indicates that the 
basin of Lake Ontario is connected by a buried channel with the Hud- 
son, but we have no proof that this pre-glacial channel is cut as low as 
the rock bottom of the lake basin. 
Third. The bottoms of some of the great lakes are now several hun- 
dred feet below the ocean level. Just how deep they are is not known, 
because they have been for ages receiving the silt washed from their 
sides, and their rock-bottoms may be covered with a great depth of mud. 
Enough is known, however, to prove that they could not have been 
drained into the ocean, when it stood at its present level. It is true that 
the continent was 500 or 600 feet higher than now at the time the old 
buried channels were cut out, but even this does not afford sufficient fall 
for a stream which should wear the rock basins of Lake Michigan and 
Lake Huron to their bottoms. These are undoubtedly 1,000 to 1,200 feet 
below the water surface and reach nearly to the old ocean level, a relative 
depth far too great for rivers to excavate rock a thousand miles from their 
mouths. 
In the important paper published by Mr. George J. Hinde, some inter- 
esting facts are stated in regard to Lake Ontario, which confirm not only 
the views advanced in Chapter XXX as to the glacial origin of our lake 
basins, but also the statement made on page 79 of Volume I, that Lake 
Ontario was formed by a glacier moving westward from the Adirondacks 
and Laurentian hills. They are contained in the paragraph given below, 
taken from page 11 of the paper before quoted: 
““T will give a very striking instance of glacial action on the shores of 
Lake Ontario, which seems to me to furnish strong proof of the basin of 
this lake at least having been scooped out by the ice. At its easterly 
end, where the channel of the St. Lawrence commences, I have traced 
the deep glacial strie and furrows on one of the islands of Potsdam 
sandstone from one hundred feet above the water’s level down to the 
water’s edge, until they disappeared beneath the lake. These striz, 
like the generality of those abundantly seen in this district, run towards 
the south-west. rom thence I have crossed the lake to its south-western 
shores, about one hundred and eighty miles distant from the place where 
“ By a typographical error stated in Volume I, page 13, to be O74 feet, but correctly 
stated in Report of Progress, 1869, page 25, where the same paragraph appears. 
