16 Mr. R. Bruce Foote on the occurrence of 



altered in color — generally having become darker — many 

 however have undoubtedly been bleached. 



In a few specimens, this bleaching process has gone so far 

 that the stone has in parts become perfectly white and its 

 texture closely resembles that of fine loaf sugar, but it is not 

 quite clear that this may not have been the state of the 

 stone when taken in hand to be converted into an Imple- 

 ment. 



The specimens found exposed on the surface by denuda- 

 tion of the rock in which they had lain imbedded are al- 

 most invariably much more weathered than those disco v ered 

 in situ — showing thus that the greatest amount of weather- 

 ing results from perfect exposure to atmospheric influences. 



The color of the Implements is considerably affected by 

 the nature of the matrix : especially in the massive latcritic 

 conglomerate by the amount of iron contained in it. 



The dendrites on the chipped surface which are regarded 

 as one proof of genuine antiquity in the case of the Euro- 

 pean flint Implements, occur rarely if ever on the Indian 

 Implements. Out of nearly 100 specially examined not one 

 showed these dendritic markings. 



Films of carbonate of lime encrusting the Implements are 

 of very common occurrence ; indeed in various places the 

 cementing medium of the conglomerate consists largely of 

 Kunkur which adheres strongly to the surfaces of the 

 enclosed Implements, as in the case, of the hatchet shaped 

 Implements figured on Plates XI and XII. 



The numerous quartzite Implements derived from the 

 quarternary formations of the Madras and North Arcot 

 Districts present as already mentioned a considerable variety 

 of form. 



Three leading classes may conveniently be distinguished, 

 which generally coincide with the divisions recognized by 



