1881 .] 
137 
[Wright. 
which, like the animals of Europe under similar circumstances, 
have since migrated to the colder regions of the north. But 
the fact remains that fossil animal bones have actually been 
discovered in these gravels, and when we call to mind to what 
a limited extent they have as yet been examined we may reason- 
ably expect more to be found hereafter. 
I limit myself to a general statement like this in regard to 
the marked resemblance of the locality, and the precisely similar 
character of the gravels at Trenton, New Jersey, to what I have 
seen in many localities in Europe, which have yielded true 
palaeolithic implements, and I leave in more competent hands the 
discussion and determination of the true geological character of 
the gravels of the Delaware valley. 
Speaking then merely from an archaeological stand-point, I do 
not hesitate to declare my firm conviction that the rude argillite 
objects found in the gravels of the Delaware river, at Trenton, 
New Jersey, are true palaeolithic implements. 
AN ATTEMPT TO ESTIMATE THE AGE OF THE PALAEO- 
LITHIC-BEARING GRAVELS IN TRENTON, N. J. 
BY G. FREDERICK WRIGHT. 
Four years ago Professor Shaler concluded his brief and 
cautious report upon the gravel beds which form the subject of 
the present paper, by expressing the “ hope hereafter to furnish a 
detailed account, of the geology of these gravel beds, and to 
support these preliminary statements by evidence in the way of 
sections and maps.” (Report of Peabody Museum for 1876, Vol. 
II. p. 47.) It is greatly to be regretted that the pressure of other 
duties prevented him from carrying out his designs. Meanwhile, 
facts bearing upon the solution of this interesting problem have 
been rapidly accumulating, until now we apparently see the 
beginning of the end. 
Briefly stated, the progress of discovery has been this : In the 
Annual Report of Professors Cook and Smock, State Geologists 
of New Jersey for 1877, the southern limit of the ice field 
during the glacial age was indicated. (See pp. 9-19.) The 
