Trans..N. Y. Acs Sci. 10 Oct. 15, 
tres of glacial action. These two periods are distinctly separated by 
a milder ‘‘ Interglacial” epoch. But this twofold character has not 
been so clearly recognized on this side of the Atlantic, although some 
evidences of it have been coming to view of late. Among the most 
interesting features of the study of the Delaware valley, is the clear 
and satisfactory indication that it has now given of the distinct exis- 
tence of the two Ice-periods, here as well as abroad. 
There was nothing at Trenton to show this fact. The gravels there 
were plainly of Glacial age, as above stated ; and that was all. But on 
studying the deposits of the Delaware valley lower down, near Phil- 
adelphia, the important fact comes to view that the continuation of 
the Trenton gravel there rests upon, and is distinct from, a series of 
deposits which are unmistakably those from the melting of the great 
ice-sheet. To Professor LEWIs is due this most interesting discovery. 
He has given the names of the ‘‘ Philadelphia Red Gravel,’”’ and the 
‘* Philadelphia Brick-clay,” to the two members into which these 
lower (‘‘ Champlain”’) deposits are divided, and has described their 
characteristics quite fully and clearly. Over these, and evidently 
later, is the dark-colored Trenton gravel, more fully developed 
higher up the valley, and containing these earliest human imple- 
ments. 
It appears, then, that we have at Trenton a deposit, ancient indeed, 
but not so far back in time as was at first supposed. The presence of 
man during the second Glacial period in Europe is abundantly familiar ; 
and the earliest remains there found certainly take us back to the pre- 
ceding Interglacial time. The relics found in the Delaware gravels, 
therefore, are not so ancient as those of the earlier Paleolithic of the 
Old World, but correspond seemingly with those of the ‘‘ Reindeer 
Epoch,” a period of cold climate, in which the animals now withdrawn 
to the Alpine heights and the Northern latitudes, ranged over Central 
Europe, and when man lived and hunted and fished in a sub-arctic 
life, much as the Eskimo people do to-day. Prof. LEwis has, there- 
fore, suggested the name ‘‘ Eskimo Period,” as a designation for this 
time. He is disposed to think that the rude people who wrought and 
used these argillite implements by the banks of the icy-flooded Dela- 
ware were near of kin to the present occupants of Arctic America. 
This view, it may be added, gains interest and force from the indica- 
tions gathered from the early Northmen’s recorded visits to the New 
England coast, at which time it would seem that the natives whom they 
encountered were not the Indian tribes, but a people similar to the 
Eskimos,—a race which had completely disappeared in the four or five 
centuries that passed before the English discoveries and settlements. 
At any rate, however, we may accept the term Eskimo period as hap- 
