504 GEOLOGY. 



it was thus contemporaneous with the " Iron age " of Europe and entirely 

 overlapped the " Bronze age." 



The chief points brought into question by the more critical inquiries 

 of recent years were (1) the reference of the ruder artefacs to a stage 

 of art more primitive than that of the Indians and other aborigines, 

 and (2) the reference of the gravels and other superficial formations 

 in which they were found to the glacial period. 



By a series of notable investigations relative to the first, Holmes 1 

 reached the firm conviction that the early inhabitants of the country, 

 like the later Indians, resorted habitually to gravel-beds and to out- 

 crops of appropriate rock to procure the raw material for their stone 

 artefacs, and that it was their custom to test and to rough-out the 

 material on the ground, leaving the chippings and the rejected mate- 

 rial scattered about. This preliminary work appears to have been 

 done wholly by rough percussion with cobbles and other natural forms 

 of stone picked up on the ground and used as hammers. The roughed- 

 out flakes and other half-shaped forms that promised to work up prop- 

 erly, were usually taken to other sites for the finishing work. This 

 half-w T orked material seems often to have been cached in quantity, 

 and to have been material of trade. The more delicate and tedious 

 work of final shaping was apparently done more leisurely, and as need 

 required, at their dwelling sites or other convenient places, and to 

 have been done by skillfully applied pressure rather than by percus- 

 sion. An example of the refuse deposits on the face of the gravel 

 bluff from which the material was taken is shown in Fig. 568. A 

 selected series of rejects, showing progressive stages of reduction, is 

 shown in Fig. 569. A full series of the stages of manufacture, as thus 

 interpreted, is shown in Fig. 570. 



By virtue of this separation of the process of manufacture into 

 two parts, there arose a geographic separation of the products, a fact 

 of importance in interpretation. The rude failures and rejects, together 

 with the extemporized hammer-stones, cores, flakings, and chips, were 

 scattered about the sites of the raw material, while the completed 

 implements were liable to become fossilized, as a rule, only about the 



1 Holmes, W. H., A Stone Implement Workshop, Am. Arthropologist, Vol. Ill, 

 1890, pp. 1-2G; Review of the Evidence Relative to Auriferous Gravel Man in California, 

 Smith. Rept. 1900, pp. 417-472; Stone Implements of the Potomac-Chesapeake 

 Tidewater, Ann. Rept. Bureau of Eth., 1893-94, pp. 1-152, and Jour, of Geol., Vol. I. 



