354 GLACIAL DEPOSITS IN NORTH AMERICA. CHAP. XVJIT. 



of time, which is wanting in the other localities, namely, 

 the test afforded by the recession of the falls, an operation 

 still in progress, by which the 'deep ravine of the Niagara, 

 seven miles long, between Queenstown and Goat Island, has 

 been hollowed out. This ravine is not only post-glacial, but 

 also posterior in date to the fluviatile or mastodon-bearing 

 beds. The individual therefore found fossil near Groat Island 

 flourished before the gradual excavation of the deep and long 

 chasm, and we must reckon its antiquity, not by thousands, 

 but by tens of thousands of years, if I have correctly estimated 

 the minimum of time which was required for the erosion of 

 that great ravine.* 



The stories widely circulated of bones of the mastodon 

 having been observed with their surfaces pierced as if by 

 arrow-heads, or bearing the marks of wounds inflicted 

 by some stone implement, must in future be more carefully 

 inquired into, for we can scarcely doubt that the mastodon 

 in North America lived down to a period when the mammoth 

 coexisted with man in Europe. But I need say no more on 

 this subject, having already (p. 200) explained my views in 

 regard to the evidence of the antiquity of man in North 

 America, when treating of the human bone discovered at 

 Natchez, on the Mississippi. 



In Canada and the United States, we experience the same 

 difficulty as in Europe, when we attempt to distinguish 

 between glacial formations of submarine and those of supra- 

 marine origin. In the New World, as in Scotland and 

 England, marine shells of this era have rarely been traced 

 higher than five hundred feet above the sea, and seven hun 

 dred feet seems to be the maximum to which at present they 

 are known to ascend. In the same countries, erratic blocks 

 have travelled from N. to S., following the same direction as 



* Principles of Geology, 9th ed. p. 2 ; and Travels in North America, TO! i. 

 p. 32, 1845. 



