hrdliCkaI stone INDUSTRIES OP THE ARGENTINE COAST 



135 



merit forms. The result of the hammer stroke varied with the 

 strength of the blow, the character of the pebble material, and the 

 degree of hardness of the* anvil-stone. The first stroke, if strong, 

 shattered the pebble, split it into nearly equal parts, or removed 

 flakes from one or both faces. When the anvil was of hard stone, 

 the lower end of the pebble was also fractured, yielding flakes identi- 

 cal with those produced by the direct impact of the hammer. When 

 the pebble was of tough or refractory material, several strokes were 

 often delivered and with increasing vigor before even a single flake 

 of moderate size was driven oft*. Continuation of the effort was 

 encouraged by the fact that satisfactory flakes were often secured 

 after the end of the pebble had become well battered. When it 

 became apparent that further effort must be futile, the mutilated 

 pebble was abandoned as mere waste. But whether good flakes were 

 secured or not, the ends of the pebble under the hammer took forms 

 entirely familiar to the student of the Argentine artifacts. In many 



Fig. 22. Adventitious origin of the creseentic edge and the gouge shape of the pebble nucleus. 

 a, The arrow point indicates the direction of the hammer blow. 6, The flake removed and the 

 slightly hollow bed left, c, The result of additional blows on the upper end of the pebble. 



cases the fractured ends developed an incipient, yet purely adven- 

 titious, edge which was often bruised and dulled in such a way as to 

 present the appearance of wear from use in some kind of manual 

 operation. 



Furthermore, it should not escape attention that the hollowed 

 out, gougelike edge which appears in many cases and is interpreted 

 by some to be the result of design, is purely adventitious. This is 

 proved by the experiments made. The hammer stroke on the end 

 of the pebble removes a flake from one face, leaving a slightly con- 

 cave bed, which is deeper at the point of percussion (fig. 22, a), and 

 a creseentic edge (fig. 22, h). A few additional strokes, designed to 

 remove flakes from the other face of the pebble nucleus, bruises this 

 edge and possibly removes small chips, giving the appearance of 

 wear in use, and at the same time often deepens the notch, as shown 

 at c. Proof that this nucleus is an implement showing design and 



