12 SUTCLIFFE, Tendencies in PrcJiistoric AntJnopology. 



amples of the same type and still more so by proof of a 

 gradual evolution of form of the implement with time. The 

 flints which Sir E. Ray Lankester has named Rostro- 

 carinate implements occur in considerable number (twenty 

 or more), and can be handled to a certain extent. He 

 offers no satisfactcr)- suggestion as to their use. The idea 

 that the smooth under-surface was used for flattening 

 and smoothing skins seems purely fanciful. The surface is 

 usually more or less concave, and in the more richl)' flaked 

 examples so roughened by the aretes of the chi[)sas to be 

 useless for such a purpose. In others it is too small, and 

 in some does not exist. In any case such a view provides 

 no explanation of the lateral flaking It is conceivable 

 that they could have been used as percussion implements, 

 but their form is not all adapted to such use ; such a 

 flint as number H, largely flaked all over and with a 

 blunt point, is opposed to such a view. 



It is, in fact, very difficult indeed to imagine any use 

 for them. The evidence that they are of human handiwork 

 rests very largely on the occurrence of a number of 

 specimens of similar form. Proof of this particular nature 

 is exposed to a psychological objection. Every geologist 

 who has collected largely from one formation is aware 

 after a time that nodules of certain shapes are much more 

 likely to contain fossils than those of other forms. The 

 result of this is that instinctively and quite sub consciously 

 he selects such nodules, disregarding, and, in fact, not 

 realising the presence of those of other shapes. Exactly 

 the same thing takes place in the ca.se of flints — the 

 collector is sub-consciously or even consciously on the 

 look-out for certain forms, and will in the end reject stones 

 which do not conform — roughly it ma}' be — to the objects 

 of his search. Perhaps the finest example of this actior. is 

 to be found in the Kentish " Plateau Eoliths," where the 



