REVIEW OF GEOLOGICAL STEUCTUHE. 47 



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 sufHcient 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 

 «lepth far too great for rivers to excavate rock a thousand miles from their 

 mouths. 



In the important paper published by Mr. Gteorge 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: 



" I 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 strise 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 striae, 

 like the generality of those abundantly seen in this district, run towards 

 the south-west. From 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 l)e 274 feet, bat correctly 

 stated in Report of Progress, 1869, page So, where the same paragraph appears. 



