*S. H. Warren — Tlie EolUhic Controversy. 551 



always chip flints in the same way, and that it is only man who can 

 chip them in different ways. 



Thus my opponents in traversing each other show the logical 

 unsoundness of their own arguments. 



Another objection which has been raised, notably by Mr. C. J. Grist,^ 

 against the theory of the origin of eoliths by movement under pressure 

 in geological deposits, is that there are certain superficial drifts in 

 which solifluction has had an obvious shai'e which at the same time do 

 not yield eoliths. One must take into consideration in such cases — 



1. Whether the drift in question contains an abundance of raw 



material of suitable size and shape for the making of eoliths. 



2. Whether the flint surfaces show striations similar to those 



which are characteristic of the ' eolithic' Chalk down drifts. 



If these two conditions are realized, then the case is a valid 

 objection against my theory ; and it requires to be given its due 

 weight. If, on the other hand, this is not so, then the objection has 

 no application against my theory, because the conditions of that 

 theory are not fulfilled. This particularly refers to the eoliths of 

 Kentish type ; but, as I endeavoured to show in the paper published 

 in 1905, there are other groups of eoliths, standing somewhat apart 

 from these, which I believe owe their form to different causes. 



In general answer to the objections of Professor Schwartz and 

 Sir Hngh Bevor, Mr. Reid Moir and Mr. C. J. Grist, which are 

 referred to above, it is ray experience that the characters of the edge- 

 chipping of the group of eoliths found in any geological deposit is 

 dependent partly upon the character of the raio material which is locally 

 availalle and partly upon the geological forces which have acted upon 

 that material. The direct evidences for the operation of these forces 

 are found, broadly speaking, in striation of the flint surfaces indicating 

 ice- or soil-abrasion, and contusion and reticulation of the surfaces 

 indicating water-abrasion. 



If the eoliths were human implements it appears to me that we 

 should expect that their characteristics would be independent of 

 associated geological forces, but would be dependent upon the relative 

 ages of the deposits containing them. As a matter of fact we do not 

 find that earlier deposits consistently contain more primitive eoliths 

 and later deposits more advanced eoliths. In a broad view of the 

 evidences, the characteristics of eolithic groups bear no discoverable 

 relation to the age of the deposits containing them. 



There are also other processes and conditions of flint chipping which 

 have their own special characters, such as dead crushing without 

 movement,^ and consequently without associated striations, but the 

 two processes mentioned above are generally the most important. 



There is only one way to become acquainted with the characters of 

 flint chipping which belong to different mechanical processes, and 

 that is by first-hand knowledge gained by following the work out 

 for oneself in the simple endeavour to find the truth. 



1 C. J. Grist, Journ. Antbrop. Inst., vol. xl, p. 198, 1910. 

 " This is pcarticularly evident in the Reading Beds at Harefield, where I first 

 found these forms on a recent visit of the Geologists' Association. 



