VIII 
THE ANTIQUITY OF MAN IN NORTH AMERICA 
441 
we thus have the proofs of man’s existence carried back not 
only to the end of the Glacial epoch, but perhaps to its very 
commencement . 1 
Palceolithic Implements in North America 
We now come to the very interesting discoveries of Dr. 
Charles C. Abbott, of Trenton, New Jersey. In the ex- 
tensive deposits of gravel in the valley of the Delaware, fresh 
surfaces of which are continually exposed in the cliffs on the 
river’s banks, he has found large numbers of rude stone im- 
plements, almost identical in size and general form with the 
well-known palaeolithic implements of the valley of the Somme. 
These have been found at depths of from five to over twenty 
feet from the surface, in perfectly undisturbed soil, and that 
they are characteristic of this particular deposit is shown by 
the fact that they are found nowhere else in the same district. 
Large boulders, some of very great size, are found throughout 
the deposit, and in one case Dr. Abbott found a well-chipped 
spear-shaped implement immediately beneath a stone weigh- 
ing at least half a ton. Professor N. S. Shaler, of Cambridge, 
Massachusetts, after examining the locality and himself ob- 
taining some implements in situ, says, “I am disposed to 
consider these deposits as formed in the sea near the foot of 
the retreating ice-sheet when the sub-Glacial rivers were pour- 
ing out the vast quantity of water and waste that clearly were 
released during the breaking up of the great ice-time.” Dr. 
Abbott, however, adduces facts which seem to prove that 
some part of the deposit at all events was sub-aerial, for he 
states that the very large boulders often have immediately 
under them a foot or more of soil between the lower surface 
of the stone and the gravel, and that this layer often extends 
some distance laterally, showing that it formed a land surface 
on which the boulders rested, and which was subsequently 
removed by water action, except where thus protected. At 
any rate we may accept Professor Shaler’s conclusion : “ If 
these remains are really those of man, they prove the exist- 
ence of inter-Glacial man on this part of our shore.” That 
the implements are of human workmanship is quite certain, 
and the fact stated by Professor Shaler himself, that “ they 
1 Annual Report of the State Geologist of Minnesota, 1877, p. 60. 
