94 SCIENCE PROGRESS 



removed by blows delivered principally upon the flat ventral 

 surface, or base of the triangle, and a cutting edge (C) formed in 

 opposition to that at B, which, as we have seen, was the keel 

 of the more primitive type of implements. 



The author has been able to examine a large number of early 

 palaeolithic implements in various public and private collec- 

 tions and has recognised many specimens which, though 

 exhibiting the two cutting-edges of the normal palaeolith, 

 nevertheless show in their profile a marked resemblance to the 

 profile of the rostro-carinate implements (fig. 5). That is to 

 say that one edge of these early palaeoliths is markedly curved 

 towards the anterior region of the implement, while the other 

 edge is much straighter. 1 He has noticed also that many of 

 these specimens exhibit the remains of either the dorsal or 

 ventral surfaces of the rostro-carinate form. Such a resem- 

 blance would be expected if the palaeoliths were evolved from 

 the rostro-carinates, and it is very significant that such forms 

 should occur so freely in the earliest palaeoliths which are 

 nearest in point of time to the rostro-carinates. 



The author has experimented extensively in the flaking of 

 flint, and has himself produced flint implements of early palaeo- 

 lithic type by following the procedure outlined above, and he 

 has found that in several cases the outline of the rostro-carinate 

 form has been preserved. He has found also that the remains 

 of either the dorsal or ventral surfaces of the rostro-carinate 

 are sometimes left at the butt-end or posterior region of the 

 implement. It has been the custom to figure and regard 

 palaeolithic implements with their points uppermost, and in 

 consequence the remains of the dorsal or ventral surfaces have 

 been spoken of as " lateral platforms." But if these specimens 

 are regarded with the point to the left, or the right as the case 

 may be, these platforms are no longer lateral, but dorsal or 

 ventral, and their true significance can be recognised. 



Fig. 6. — This drawing represents a highly evolved palaeo- 

 lithic implement in which both edges are symmetrical, and the 

 likeness to the ancestral rostro-carinate form has almost 

 disappeared. 



Fig- 7- — Represents an ovate palaeolithic implement. These 



1 The downward curvature of one edge represents the curving of the keel 

 towards the anterior region, while the straighter edge represents the flat ventral 

 surface of the rostro-carinate form. 



