146 THE POPULAR SCIENCE MONTHLY. 



ceeding glacial flood, more and more sand, gravel, and great 

 bowlders were rolled down from the rock-ribbed valley beyond 

 and spread upon the open plain through which the present 

 stream unruffled flows. 



The land was somewhat depressed then, and the water flowed 

 at a higher level, but nothing unfavorable to man's existence ob- 

 tained in the whole region. As a skilled geologist has pointed 

 out, " The northern ice was one hundred miles away, and did not 

 prevent primitive man from assembling about the low and hos- 

 pitable shores of the miniature sea, . . . and over the bosom of 

 the bay, little affected by tide because of its distance from the 

 ocean, and little disturbed by waves because of its shoalness, 

 palaeolithic man may have floated on the simplest craft, or even 

 have waded in the shallow waters." Ay ! may have ; but did he ? 

 "What evidence is there that that most primitive of mankind, who 

 left such abundant traces of his presence in the valley of many 

 a European river, and also in Asia and Africa, was ever likewise 

 here in eastern North America ? It is precisely the same evi- 

 dence rude stone implements of the simplest type, often but 

 slightly modified cobbles merely, that were found to be more 

 effective by having a chipped and jagged edge, rather than the 

 smooth and tapering one that water-wearing produces. These 

 same worked stones in other countries always of flint, but in 

 New Jersey of argillite, a slate-like stone that has been altered 

 by heat, and possesses now a conchoidal fracture these occur in 

 the Delaware gravels; and the vivid pictures of glacial time, 

 with primitive man a prominent feature thereof, that have been 

 given by Wright, Wilson, Haynes, McGee, Upham, Cresson, Bab- 

 bitt, and others, are doubtless familiar to all readers of recent sci- 

 entific literature. 



In associating man with ancient river valleys, we are too apt 

 to think only of the stream, and ignore the surrounding country. 

 Though largely so, palaeolithic man was not strictly an amphibi- 

 ous creature ; for instance, on each side of the ancient Delaware 

 River extended wide reaches of upland forest, and here, too, the 

 rude hunter of the time found game well worthy of his ingenuity 

 to capture, and so powerful that all his wit stood him well in 

 need to escape their equally determined efforts to capture him. 

 While the seal and walrus disported in the river ; while fish in 

 countless thousands stemmed its floods; while geese and ducks 

 in myriads rested upon the stream, so, too, in the forest roamed 

 the moose, the elk, the reindeer, the bison, the extinct great 

 beaver, and the mastodon, all of which, save the elk, had long 

 since left for more northern climes when European man first 

 sighted North America. 



The association of man and the mastodon is somewhat start- 



