its
age we shall also determine at least one point in the antiquity of
man, for we know the implements are as old as the gravels. It is not
necessary for our purpose to give more than the results of the careful
labors of others in this direction. We may be sure that this question
has been carefully studied. When the implements were first discovered,
the gravels were considered of glacial origin, and to that period they
were assigned by Dr. Abbott. Subsequently Prof. Lewis, a member of
the Pennsylvania State survey, decided that they were essentially
post-glacial--that is, more recent in time than the Glacial Age.<56>
Still more recently Prof. Wright, of Oberlin, but also of the State
survey of Pennsylvania, concludes that they are, after all, a deposit
made at the very close of the Glacial Age.<57>

He thinks the sequence of events were about as follows: When the ice of
the Glacial Age reached its greatest development, and came to a pause in
its southward march, it extended in an unbroken wall across the northern
part of New Jersey, crossing the Delaware about sixty-five miles above
Trenton. In front of it was accumulated the great terminal morain--a
long range of gravelly hills still marking its former presence.

It is certain that the close of the Glacial Age was comparatively
sudden, and marked by floods far exceeding any thing we are acquainted
with at the present day. For, when the formation of the ice ceased, we
must bear in mind that the country to the north of the terminal morain
was covered with a great glacier, in some places exceeding a mile
in thickness. When glacial conditions were passing away, and the ice
commenced to melt faster than it was produced, the thaw would naturally
go on over the entire field at an increasing rate, and hence would
result floods in all the rivers.

He considers the gravels in question to have been deposited near the
close of this flooded period, when the land stood at about its present
level and the glaciers had retreated perhaps to the Catskill Mountains.
The rivers were still swollen and would be heavily charged with coarse
gravel brought from the morains and lying exposed on the surface of the
ground vacated by the glaciers.<58>

Probably but few geologists will take exceptions to these views. Thus we
have very satisfactory reasons for connecting these Paleolithic people
with the close of the Glacial Age--a conclusion to which the scattering
discoveries mentioned in the