MAN AND THE GLACIAL PERIOD. 623 



" stone ") ; while the later stone implements are classified 

 as neolithic (Gr. j/eo?, " new," and \t0o?, u stone "). 



Palaeolithic implements are said to be old, however, not 

 because of any inelastic theory of evolution, implying that 

 people using rude arts always precede those who are more 

 skilled, but the age of these implements as a class is deter- 

 mined by the fact that they have been found in undisturbed 

 glacial deposits or under other geological conditions showing 

 their antiquity. Such implements are unquestionably older 

 than others found upon the surface ; and, in their case, the 

 evidence of great age is definite and conclusive, while the 

 antiquity of the implements found upon the surface is sub- 

 ject to more or less of doubt. If man inhabited the region 

 bordering upon the great ice-sheet when it extended to its 

 farthest limits, his implements should be found near the sur- 

 face of the ground outside those limits ; and such might be 

 of even greater age than those which are found in stratified 

 glacial deposits themselves. Also, as the ice receded, it is to 

 be expected that man would follow it in its slow recession 

 (as the Eskimo does to-day in Greenland) and that his imple- 

 ments would be lost upon the surface. How long he may 

 have continued thus to use implements of palaeolithic type 

 can not readily be determined. Mr. Thomas "Wilson, of the 

 Smithsonian Institution, has already collected, or had reported 

 to him, many thousand implements of the palaeolithic type 

 found in various parts of North America. In almost all 

 cases these were found upon the surface, and there is no 

 means of determining their age except from their general 

 weathered appearance, as implements of the same forms have 

 been made and used all through the Stone age. 



About the year 1860 interest in the subject of man's an- 

 tiquity received a new and definite impulse in connection 

 with the discoveries of Boucher de Perthes in northeastern 

 France. As long ago as 1841 this indefatigable investigator 

 discovered rudely fashioned stone implements in high gravel 

 terraces along the valley of the Somme at Abbeville. An 

 account of his discoveries was published in 1846. Little at- 



