145 
[Wright. 
1881 .] 
so abundant that doubtless the whole channel was silted up so 
that the bed of the river was considerably above that it now 
occupies. At Trenton it flowed over and through an extensive 
delta of coarse gravel forty feet above its present level; and 
above Trenton, over an accumulation of gravel from fifteen to 
twenty feet above the present high water mark. This period was 
marked by the presence of the mastodon and other extinct 
animals (the skeleton of a mastodon having been found in the 
Trenton gravels) and by the advent of palaeolithic man to the 
neighborhood of Trenton. 
3. During the Terrace epoch the river worked its way down 
through the delta of gravel at Trenton, and has since eroded its 
present channel which is about two miles wide at that jioint. 
Higher up, where the current is swift, the lateral erosion in 
recent times has been small. 
4. To determine approximately the date of the earliest 
evidence of man’s appearance at Trenton we have as data, (1) 
The amount of erosion in the palaeolithic gravels at Trenton. 
(2) The general evidence from other sources bearing upon the 
date of the close of the Champlain epoch in this country. As 
bearing upon this, several terrestrial time-measures are accessible, 
the most important of which are the recession of various water- 
falls, like those of Niagara and St. Anthony, which occupy 
post-glacial beds ; and the extent to which sediment and peat 
have accumulated in post-glacial lakes and kettle holes. It will 
be much safer to draw conclusions from such tangible data as 
these, than from the distant regions of astronomy, or from the 
uncertain rate at which the evolution of plants and animals has 
proceeded, or the development of man has progressed. 
Mr. Lucien Carr said that in September 1878, he had visited 
Trenton in company with Professor Whitney of Cambridge, and 
that together they had examined the implement-bearing gravel 
bed. During the investigation it was his good fortune to find one 
specimen in place, under such circumstances that it must have 
been deposited at the time the containing bed was laid down. It 
was in the ravine which cuts through the bluff near Dr. Abbott’s 
house, in a fresh exposure made by a recent heavy storm, and 
PROCEEDINGS B. S. N. H. VOL. XXI. 10 NOVEMBER, 1881 . 
