72 MEETING, MONDAY, APRIL 4. 



is very important) may be found in the London Quarterly 

 Journal of Science for April, 1875. There is nothing to 

 show that the portion of the gorge extending from the 

 Whirlpool up to the present site of the Falls is not also 

 preglaeial, but many things to indicate that it is the true 

 continuation of the old preglaeial channel. The distance 

 between the present cataract and the Whirlpool is about 

 four miles, or half that of the whole gorge, and the posi- 

 tion of the strata is such that through this portion of the 

 oroi-o-e the rate of retrocession must have been much 

 slower than that below the whirlpool. One of the evi- 

 dences that this upper portion of the channel belongs to 

 the preglaeial times is that it is much wider than that 

 from the Whirlpool to Lewiston. Now, if we suppose 

 that, when the cataract had worn out the gorge from 

 Lewiston to the Whirlpool, it struck the preglaeial gorge 

 and above that point had simply to scour out the loose 

 material from it, the measure of the time since the glacial 

 age is that required by the river to form the gorge below 

 the Whirlpool plus so much of the upper end as was not 

 already in existence. What this last element is we have 

 no means of telling precisely, but the time required for 

 eroding the lower section could scarcely have been more 

 than 20,000 and very likely was less than 10,000 years, 

 that being very much the easiest part of the work to be 

 done. 



The thing which the investigations of Dr. Abbott and 

 Professor Lewis have settled is that man was in America 

 before the close of the glacial epoch, so that now any in- 

 vestigations which help to assign a date to that period, 

 help to determine the minimum chronology of man's ex- 

 istence on this continent. The kames and moraines of 

 New England furnish a promising field in which to look 

 for further evidence upon this most interesting question. 



