878 The American Naturalist. [November, 
(Fig. 1). The stone was turned in the hand and a second series 
of blows given on the other side, and the result was a “ double- 
turtle-back,” (Fig. 2). The third stage is described in an un- 
Free-hand on direct percussion ; 
first step in shaping an implement 
from a bowlder.. (Prof. Holmes 
fig. 6). 
certain and indefinite way, 
rather out of keeping with the 
rest of the paper. “If the form 
(of the first-two stages) develop- 
ed properly, the work was con- 
tinued into what I have called, 
for convenience, the third stage. 
It consisted in going over both 
sides a second and perhaps a 
third time, securing, by the use 
of small hammers and by deft 
and careful blows upon the 
edges, a rude but symmetrical 
blade. A profile is given at p. 
in Plate IV.” It is to be re- 
marked, as a matter of impor- 
tance, that his manipulations 
are confined to the first two stages and do not enter upon or 
pretend to show the third process which reduces the object 
Fic. 2. ; 
Direct percussion; manner of Striking where the edge is sharp. 
(Prof. Holmes fig. 7). 
from a thick and rude implement into “a straight and 
symmetrical blade less than one-half inch in thickness.” 
There his process fails, and he has not, nor do I believe he 
