HBOLifKA] STONE INDUSTRIES OF THE ARGENTINE COAST 101 



covered by sedimentary deposits consisting of red Pampean and pre- 

 Pampean (Araucanean) clays, and is exposed only at a number of 

 points of limited extent. This coarse-grained quartzite is the result 

 of the transformation of sedimentary deposits of coarse sand and 

 gravel and presents a texture and density which make dressing it 

 impossible. Man who in former times inliabited this locality was not 

 able, therefore, to employ this material for the manufacture of his 

 implements. 



"But at the epoch of the Inter-Ensenadean transgression the sea 

 threw on the beach water-worn pebbles which the marine currents 

 brought from the coast of Patagonia. These pebbles fractured with 

 greater facihty. 



"The Homo pampsaus probably commenced to gather these stones 

 and to break them between two blocks of quartzite, in order to utihze 

 the pointed and edged chips which resulted. Later, and with ex- 

 perience, there, came to him the idea that these pebbles could be 

 fashioned in a more uniform manner by making a cutting edge at 

 one of their extremities. Not knowing true flaking by percussion, 

 but only breaking by means of strokes with a stone hammer and with 

 the help of a block of quartzite employed as an anvil, he tried, prob- 

 ably, to split the pebbles, supporting them on the anvil-stone. He 

 attempted this splitting not as in simple breaking, but by strokes at 

 one end of the long axis of the pebble." 



The technique of making the implements Ameghino explains as fol- 

 lows (p. 193) : 



' ' I shall call the two ends of the long axis of the pebbles its two poles. 

 That placed on the anvil-stone was the inferior pole, while the other, 

 destined to receive the blows of the hammer, was the superior one. 

 To obtain the desired instruments, the man made a selection from 

 among the pebbles, etc., always utiUzing the more elongated and 

 flattened ones, one extremity of which was to be held by the hand, 

 while the other was to be fashioned to a cutting edge. The larger 

 end, the one easier to hold in the hand, was the inferior pole, by which 

 the pebble was placed upright on the block of quartzite. The other 

 end, which pointed upward, was the superior pole, on which the 

 operator directed blows until he obtained the form he desired." 



At this point Ameghino explains the mode of production of the 

 anvil-stones (pp. 193-194): 



"Naturally, during the first trials at shaping the stone, the rounded 

 butt of the pebble, which was placed on the block of quartzite, must 

 have tended to slip thereon. Possibly in some blocks a natural 

 depression insured a vertical position of the pebble in such a way that 

 the stone could not slide, notwithstanding the blows of the hammer. 



"From that moment man chose pieces of quartzite which appeared 

 to him most suitable and cut into their surfaces small elliptic cavities 



