306 PROCEEDINGS OF THE ACADEMY OF [1880. 



epocli cannot be proved in America, the facts here observed will 

 indicate a much more recent date for the disappearance of the 

 great glacier than has been assigned to it. The period of the 

 Trenton gravel flood, whether contemporaneous with a glacier or 

 not, is the period of the last geological deposits here known- the 

 recent mud-flats being alone excepted. 



We have now glanced at the characters of the Trenton gravel, 

 and have indicated, so far as the facts at hand allow, its position, 

 origin, and relative age. 



It is in this gravel that the writer's friend, Dr. Charles 

 C. Abbott, of Trenton, has made the interesting discovery of stone 

 implements of human workmanship, which, in their shape and 

 characters, are quite unlike those of the Red Indians of the Atlantic 

 coast.^ He has found them imbedded at various depths in the ap- 

 parently undisturbed gravel of the cliff at Riverview Cemetery 

 and in other places near Trenton. They are of palseolithic type, 

 and differ from Indian stone implements by being larger, ruder, 

 and made from a different material. They are composed of gray 

 argillite, a rock which is found in place farther up the river, 

 and which is a Triassic shale altered and hardened bj- the heat 

 from adjacent trap dykes. They occur in positions which render 

 it extremely probable that they belong to the same age as that of 

 the deposition of the gravel, or at least to an age when it was 

 overflowed b}' the flooded river. There are two points which 

 offer strong evidence in that direction. 



The first is the fact that modern Indian implements, "neoliths," 

 are never found associated with these " palaioliths " in the gravel. 

 Although abundant on the surface, it is stated that thej^ never 

 occur at a depth of more than a few inches in undisturbed soil, 

 while the palteoliths are found often ten or more feet from the sur- 

 face. This fact alone argues a different age for the two classes of 

 implements. 



The second fact is that when found below the surface of the 

 ground, these palffioliths always occur in the Trenton gravel and 

 never in older gravels. The writer, in company with Dr. Abbott, 

 has gone over much of the ground where the implements occurred ; 

 and it was very interesting to find that it was onl^^ within the 

 limits of the Trenton gravel, previously traced out by the writer, 



^ V. Tenth and Eleventh Annual Keports of the Peabody Museum of 

 American Archaeology. 



