594 STONE IMPLEMENTS FROM SHORES OF LAKE MICHIGAN. 



roundiug aud striation of the edge could be produced- an oblique 

 movemeut would produce the oblique striatious.' 



In the operation represented in h the flake is held obliquely and the 

 edge is pushed forward, with its fractured face directed downward 

 toward the surface treated, as indicated by the arrow. This operation 

 is not unlike that of planing, and accounts for modifications in which 

 striatious run over the rough surface of the flake, which was generally 

 beneath. The divergence of the strife from the line of the long axis of 

 the flake coincides with the natural outward tendency of the move- 

 ment, and with the theory that the operator was right-handed. Flakes 

 modified in this way are usually characterized by a rounded upper end, 

 making them convenient for holding in the palm of the hand. The 

 results of incising wood and leather, and especially of incising with a 

 sawing motion, were the same. Chopping and grindino- gave charac- 

 teristic results. 



In the operation represented in c, the flake is held in much the same 

 manner as in the first instance, but is drawn in the direction of the 

 edge, as indicated by the arrow, making a cutting tool. The modifica- 

 tion shown in Plate III, /, is thus produced, the character of the 

 substance incised naturally having much to do with the rapidity of 

 wear. Scraping as already shown may produce a similar effect. Held 

 again in much the same way, repeated choi^ping blows would give the 

 chipped edge with rounded angles superimposed shown in d. 



Pressure in all cases is an important part of the operation, whether of 

 scraping or cutting, and in the experiments it was j)roductive of more 

 or less chipping of the edge in addition to the abrading effects. 



In e the flake is held by the fingers of the right hand with the rough 

 surface directed downward. If moved in this position back and forth in 

 a straight line or in a circle or ellipse over the surface subjected to its 

 action, a variety of the effects observed in the specimens may be 

 produced. 



Again, if held in the palm of the left hand,/^ the rough surface of 

 fracture uppermost, the flake may answer the purpose of a whetstone, 

 the object ground being moved back and forth in the direction of the 

 arrows. A specialized flake {b, Plate VI) is represented as the object 

 ground. In this manner the trap flake would take on exactly the 

 modification that is found in certain of the flake tools. 



Specialized flakes. — Many of the trap-flake tools have been designedly 

 specialized by means of flaking, pecking, and grinding. Degrees of 

 elaboration occur extending from a simple alteration of the serviceable 

 edge to a more complete working out of forms characteristic of the 



1 Materials of several kinds were operated upon by the author to test the rapidity 

 of wear and the nature of the effect upon fresh flakes. Wood, stag horn, Lone, hide, 

 and stone were cut, chopped, and ground. The effect when the scraping acts had 

 been carried on for some time was a smooth and polished edge, without striatious, 

 except where the material worked was itself uneven in texture. 



