1887.1 425 [Abbott. 



November last, by W J McGee before the Anthropological Society 

 of Washington. In this paper the author gives the results of his 

 examination of the surface geology of the locality in question. 

 He states that there are two deposits of gravel covering the pres- 

 ent valley, which are very distinct in origin, age and general 

 character. The older and more extensive one is composed of usu- 

 ally small quartzite pebbles, or of line quartzite sand, the latter 

 frequently colored a deep reddish-brown from the abundant pres- 

 ence of oxide of iron. This deposit has been designated by Dr. 

 Cook as the " southern drift," and by Professor Lewis as the 

 "yellow gravel." Mr. McGee has proposed the name of "Colum- 

 bian gravel. " Overlying this, for a limited area, so that it 

 forms the bed of the stream and lines its banks for some distance, 

 both above and below tide-water limits, is another deposit of 

 gravel, wholly different from the preceding, or "Columbian," in 

 that it consists of pebbles and large boulders, with some sand. 

 This is now well known as the Trenton gravel, being called so 

 from the fact that its greatest deposit is at the site of the city of 

 that name. It is an accumulation derived by water and ice-action 

 from the terminal moraine of the second or last glacial period — 

 the result of the floods that occurred during the melting and re- 

 cession of the ice-sheet. At this time the region was so far de- 

 pressed as to permit the tide to reach northward quite to the 

 terminal moraine, some sixty miles beyond the present tide limit. 

 This later deposit, then, is the most recent distinctly traceable 

 phenomenon of the last glacial epoch. 



It is in this accumulation of redistributed morainic material 

 that the rudely chipped implements are found ; and Mr. McGee 

 points out that the conditions of the country, bounding the sub- 

 merged area, were in all respects favorable for man's occupancy 

 at that time. 



Since the last occasion upon which the discoveries of rude or pa- 

 laeolithic implements from the Trenton gravel were announced to 

 this society (1883), the various exposed sections of the deposit 

 have been carefully examined by Dr. Abbott and several specimens 

 of much interest have been obtained ; and with these were two 

 fragments of human crania, found at different, and both at very 

 significant depths. No further evidence, it would now seem, was 

 required to prove the occurrence of man on the Atlantic seaboard 



