70 SIE DANIEL WILSON 



areas of this continent. With the fact before us that even now the Stone period of its 

 aborigines has not wholly passed away, careful observation is required in determining 

 the probable age of stray specimens buried even at considerable depths. 



Bui disclosures of an actual American implement-bearing drift appear at length to 

 have been met with in the valley of the Delaware. These show the primitive tool-maker 

 resorting to a granular argillite, the cleavage of which adapted itself to the requirements 

 of his rude art. Prof. Shaler, in a report on the age of the Delaware graA^el beds, 

 describes this formation as occurring from Virginia northward to Labrador, though 

 it is only in New Jersey and Delaware that the accompanying evidences of human 

 art have been thus far recovered. The New Jersey drift is made up of transported 

 material, including boulders and smaller fragments of granitic, hypogene, sandstone, and 

 limestone rocks, along with water-worn pebbles of the same granular argillite as the 

 characteristic stone implements recovered from it, to which, from their peculiar shape, the 

 name of " turtle-back celts" has been given. There is little true clay in the deposit to 

 give coherence to the mass. The type of pebble is subovate, or discoidal, suggesting its 

 form to be due to the action of running water ; and it seems probable that the stone 

 was not quarried out of the living rock, but that the pebbles thus reduced to a con- 

 venient ibrra were turned to account by the tool-maker. The researches of Dr. Abbott 

 have been rewarded by the discovery in the drift-gravel of numerous examples of this 

 peculiar type of implement, for which the one material appears to have been used, not- 

 withstanding the varied contents of the drift-gravel in which they occur. As in the case 

 of the French and English river drift, the fractured material is found in every stage of 

 disintegration. Prof. Shaler says : " Along with the perfect-looking implements 

 figured by Dr. Abbott, which are apparently as clearly artificial as the well-known 

 remains of the valley of the Somme, there are all grades of imperfect fragments, down to 

 the pebbles that are without a trace of chipping." Bat more recent discoveries in the 

 Delaware valley point to palaeolithic remains of a still earlier age. The disclosures of 

 Dr. Abbott naturally attracted attention to the region ; for there, for the first time, the 

 American arch;eologist saw the promise of disclosures corresponding in character to those 

 of the European drift-gravels. A systematic and prolonged series of investigations have 

 accordingly been carried out by Mr. Hilborne T. Cresson, under the direction of the Peabody 

 Museum, resulting in fresh disclosures of early American man. The Naaman's Creek rock- 

 shelter carefnlly explored by him, is situated in the State of Delaware, immediately to the 

 soiith of Mason and Dixon's line. There in underlying deposits, claimed to be of Post- 

 Grlacial age, rudely chipped points and other implements, all of argillite, were found; and 

 at a higher level, others of argillite, but intermingled with bone implements, and frag- 

 ments of rude pottery, and alongside of these implements lashioned of quartzite and 

 jasper. The antiquity assigned to the Delaware implements, as determined by the age of 

 the tool-bearing gravel is much greater than that of the Trenton gravels previously 

 referred to ; but though remains of fifteen diiferent species of animals, including 

 fragments of a human skull, were recovered from the cave or rock-shelter, they include 

 none but existing fauna. But the evidence of antiquity is based most confidently on the 

 discovery of palteoliths in situ in the trne Philadelphia red-gravel. Prof G. F. Wright 

 remarks, in discussing the relative ages of the Trenton and Philadelphia red gravel, 

 that both he and Prof. Lewis came to the same conclusion ; assigning the deposition of 



