438 SCIENCE PROGRESS 



If the reader will now examine the illustrations accompany- 

 ing this paper, it will be noticed that while figs. 1-6 show 

 that the force which acted on the edges of the flints removed 

 the flakes at a constant angle to those edges, fig. 7, which was 

 picked up on the sea-beach at Lowestoft, has had the flakes 

 removed from its edge at divergent angles. It will be noticed 

 also that in figs. 8 and 9, which represent flints flaked by the 

 author by means of another stone used as a hammer, the 

 specimens have had the flakes removed from their edges at a 

 constant angle. It appears, then, that these flints (figs. 1-6) 

 have been flaked along their edges by blows, and that these 

 blows have been delivered at a constant angle to those edges. 

 It is also noticeable that figs. 8 and 9, which represent speci- 

 mens flaked by the author with a hammer-stone, have had 

 their flakes removed at a constant angle to the edge. The 

 specimen represented by fig. 7, on the other hand, which was 

 found upon a shingle beach, where natural percussion has 

 opportunities for operating, has had its flakes removed at 

 divergent angles to its edge. This evidence points undoubtedly 

 to the conclusion that the edge-flaking of the specimens illus- 

 trated in figs. 1-6 is of human origin, but we will proceed to 

 a further examination of the flaking to ascertain if this con- 

 clusion is supported by other evidence. In the experiment in 

 which flints were subjected to the effects of fortuitous per- 

 cussion by shaking them in a sack, 1 it was noticed that the 

 flakes removed from the edges of the stones differed in appear- 

 ance from others removed by human blows. These differences 



(a) The squatness of the fortuitous flakes as compared 



with those removed by human agency. 



(b) The fact that the former had cut deeper into the flint, 



causing a step or ledge to appear at the point of their 

 final separation from the parent block. 



(c) The occurrence of numerous prominent ripple-marks 



upon nearly all the flakes produced by fortuitous 

 blows, as compared with their comparative scarcity 

 upon the " human " flakes. 



When the specimens illustrated in figs. 1-6 are examined, 



1 See Science Progress, July 1916, pp. 43-4. 



