36 THE POPULAR SCIENCE MONTHLY. 



bank or the collection, ten per cent to thirty per cent exhibit un- 

 mistakable traces of design, a somewhat larger percentage sug- 

 gest but do not prove design, and not more than fifty per cent 

 strike the student as natural, when the individual specimens are 

 examined separately ; and when examined collectively the corre- 

 spondence in form and mode of fracture between symmetric " tur- 

 tle-backs," " failures," " spa wis," " chips," and miscellaneous frag- 

 ments compels the cautious geologist to question whether any are 

 demonstrably or even probably natural : the series is not from 

 the certainly natural to the doubtfully artificial, but from the 

 certainly artificial to the doubtfully natural. 



The " turtle-backs " tell nothing of the customs of the makers, 

 since their function is unknown ; whether they were sinkers for 

 nets, whether they were hammers or axes used either in the hand 

 or attached to withes or handles, whether they were used as the 

 holas of the Patagonians, whether they were employed in fishing 

 first for cutting the ice and then for eviscerating and scaling the 

 fish, or whether they subserved a variety of purposes, remains un- 

 determined. The environment read from geology indicates that 

 the Trenton man was a hunter or fisherman who used and lost the 

 primitive tools of his mysterious craft within the waters rather 

 than upon the land, and thus appears to materially narrow the 

 range of hypothesis as to his activities ; but the extravagance in 

 labor indicated by the vast numbers of unworn implements sug- 

 gests that the rapid modification in environment and occupation 

 accompanying the ice-invasion outran the resulting modification 

 in appliances, and that the implements were really invented on 

 land and were but ill adapted to the new conditions ; and the in- 

 troduction of a new type of implement during the brief epoch of 

 gravel deposition gives support to the suggestion. 



So the margin of the cloud enveloping the beginnings of 

 human life in America is slowly lifting. Already there is defi- 

 nite and cumulative evidence of man's existence during the latest 

 ice epoch, with a strong presumption against an earlier origin 

 than the first Quaternary ice-invasion ; already it is known that 

 the primitive American haunted the ice front rather than the 

 fertile plain, and must have been hunter or fisherman ; already 

 his environment is so well known as to partially elucidate his 

 activities ; but the first traces of the autochthon yet found tell of 

 an intelligent being who dominated the animal world as does his 

 descendant, and thus the mystery of man's ultimate origin re- 

 mains enshrouded as darkly as ever. 



