274 THE ANTIQUITY OF MAN 
We shall commence our journey some fifty miles to 
the south of New York — at Trenton City, situated at the 
head of Delaware Bay, in the State of New Jersey. The 
great expanse of gravel on which Trenton has been 
built was deposited by the Delaware during the Ice 
age. This gravel has yielded the kind of evidence of 
which we are in search — the stone implements and the 
fossil remains of ancient man. During the most severe 
of the glacial phases the edge of the ice sheet lay only 
sixty-five miles to the north of Trenton. In the valley 
of the Delaware river the deposits laid down along the 
southern edge of the ice sheet can still be seen. The 
marginal deposit of the ice sheet — the moraine — is con- 
nected with the gravel bed on which Trenton is built by 
a terrace which descends on each side of the valley of 
the Delaware river. There can thus be no doubt that 
the Trenton gravels are deposits of the Ice age. They 
were laid down at the mouth of the river at sea-level. 
Since their deposition the land has risen, so that now the 
ancient gravel delta is 50 feet above the present level 
of the sea. 
The story of the discovery of traces of early man in 
the Trenton gravels recalls early incidents in the valley 
of the Somme. The place of Boucher de Perthes is 
taken by Dr C. C. Abbott. In 1875 the Pennsylvania 
Railroad had opened a pit in the gravel bed near 
Dr Abbott's house. Dr Abbott watched the pit from 
day to day, and ultimately found numerous examples 
of roughly chipped stone implements, recalling the 
palaeoliths found in valley terraces of Europe. They 
occurred at all levels of the gravel, and in strata which 
had never been disturbed since the date of deposition. 
Dr Abbott's discovery was received with the same degree 
of scepticism as had been extended to the earlier efforts 
of Boucher de Perthes in France. Fortunately, his 
investigations attracted the attention of Professor F. W. 
Putman of the Peabody Museum of Harvard University. 
Under his direction Mr Ernest Volk commenced a long 
series of accurate investigations which proved the truth 
