218 THE CANADIAN NATURALIST. [Vol. ix. 



thing indicates that the basin of Lake Ontario is connected by a 

 buried channel with the Hudson, but we have no proof that this 

 pre-glacial channel is cut as low as the rock-bottom of the basin." 



The buried channel at Onondaga, to which allusion is here 

 made, has not, it is true, been proved as deep as the bottom of 

 Lake Ontario at present. But it has been explored to the depth 

 below the lake level of ''414 feet, and we are not certain that 

 rock was reached in this boring." (Vol. II, p. 16.) Nor, it 

 may be added, can we be sure that this bore was made in the 

 deepest part of the channel. The buried channel at Onondaga 

 has therefore been explored almost to the level of the bottom of 

 Lake Ontario at present in its deepest part. But on the estimate 

 mentioned above of the elevation of northern land, the bed of 

 Lake Ontario at the time in question was relatively to the buried 

 channel 100 feet higher than now, and in that case the channel 

 was many feet below the lake bed, and the flow of the pre-glacial 

 Mohawk from the Ontarian vale to the Hudson river was both 

 possible and easy. 



4th. " The bottoms of some of the great lakes are now several 

 hundred feet below the ocean level," and " their rock bottoms 

 may be covered with a great depth of mud." " 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, but even 

 this does not afiford sufficient fall for a stream which should wear 

 the rock-basins of Lakes Michigan and Huron to their bottoms. 

 They are undoubtedly" (?) "1000 to 1200 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." 



The very basis of this objection is a supposition of which no 

 proof is given, that the beds of Lakes Michigan and Huron 

 are covered with 200 to 300 feet of deposit. In this way they 

 are brought down nearly to the level of the pre-glacial Atlantic. 

 But with any more moderate estimate they lay considerably 

 higher, and if this deposit is disregarded, were more than 300 

 feet above that level. If we halve Dr. Newberry's figures and 

 allow 150 feet of deposit in the beds of Lakes Huron and Michi- 

 gan, the former was between 300 and 400, the latter between 

 200 and 300 feet above the ocean. These heights would give 

 ample fall for the old Mohawk river in its course of 1000 miles^ 



