370 MAN AND THE GLACIAL PERIOD. 



overturnings and movements to which the strata have been 

 subjected during the long ages of geological time. He gives 

 photographs of some of these objects, which are to me en- 

 tirely convincing, and describes how he has surprised Nature 

 in the very act of fabricating them in an abandoned quarry 

 worked in an Eocene deposit. He thinks the " crackled " 

 surfaces can be readily explained as the result of atmos- 

 pheric action, or of hot springs charged with silex. Numer- 

 ous examples of similar changes in the surface of flint, that 

 have been noticed by himself and others in different locali- 

 ties, are instanced. Even if some have been caused by tire, . 

 this does not necessarily imply the intervention of man to 

 have produced it. Similar discoveries have also been made 

 by M. d'Ault de Mesnil, at Thenay, in Eocene deposits,* and 

 by M. Paul Cabanne, in the Gironde.f My own opinion, 

 based upon the experience of many years spent in the study 

 of flints broken naturally as well as artificially, and upon a 

 careful examination of Bourgeois's collections, is that the so- 

 called Thenay flints are the result of natural causes. 



The second locality where flints alleged to display marks 

 of human action have been found is the vicinity of Aurillac, 

 in the Auvergne, especially on the flanks of a hill called 

 Puy-Courny. They occur in a conglomerate of the upper 

 Miocene period, and are consequently much later than the 

 Thenay flints. In this conglomerate, in 1869, M. Tardy dis- 

 covered a worked flint flake which has every appearance of 

 being artificial. $ Mortillet, however, says that it was found 

 in the upper surface of the deposit, where there may easily 

 have been a mingling with the Quaternary formation ; and it 

 certainly resembles worked flakes, which are not uncommon 

 in the Quaternary. The geological determination of the 

 find may consequently be regarded as uncertain. 



The flints discovered at Puy-Courny by M. Barnes are of 

 small dimensions, and have all been produced by percussion. 

 Many of them are said to bear some resemblance to pointed 



* Materiaux, ibid., p. 246. f Id., tome xxii, p. 205. 



\ See Materiaux, tome vi, p. 94. S. Reinach, however, Descrip- 

 tion Raison. du 31usee de Saint- Germain-en-Laye, i, p. 107, n. 8, 

 calls it " gravure inexacte." 



