408 THE POZO STONE. 



Hence, the peculiar and intense weathering which the visitor 

 may see on one side of the stone was, in all probability, done ages 

 before the milder action on those sides on which the petroglyphs or 

 rock drawings are chipped, and the one on which the stone rests. 

 The rough weathering tells of a time of intermittent rainfall ; the 

 gentler weathered sides of a higher elevation of country and the 

 beginning and continuance of that rainless period which has allowed 

 of the formation of nitrates of such soluble substances as Soda and 

 Potash and the Chlorides of Copper and Silver.* 



These considerations help us also to understand how the 

 incisions on the stone have been preserved in apparently as fresh a 

 state as when cut. So conserving is the climate from whence the 

 stone was brought, that mummies, of unknown nations, with articles 

 having some religious significance, are constantly being found in an 

 excellent state of preservation. We learn, too, that the incisions 

 are upon the weathered surface of the stone because the carver or 

 carvers of the pictorial stones took up such weathered blocks of 

 rocks as were adapted for the purpose, no two being alike in shape 

 or size. 



How were the incisions made ? That they are Indian work I 

 do not doubt, but I am not inclined to agree with Mr. Thomas J. 

 Hutchinson that they were done with an iron or a copper implement. 

 Iron implements were unknown to the people who carved this stone. 

 The petroglyphs on it are extremely primitive in character, and very 

 feebly incised. Mr. R. B. White, an astute observer, in his study 

 of the "Aboriginal races of the North-west provinces of South 

 America," says " The material which the Indians used for their 

 tools was stone. * * * * The volcanic rocks of the country 

 furnished stones of suitable hardness, and the mountain torrents 

 provided pebbles already worn down into shapes, which diminished 

 the labour of fashioning them into implements. * * * * Hatchets, 

 adzes, chisles, hammers, and such-like implements of all sizes are 

 found, and, as a rule, they are beautifully fashioned and ground, 

 and were made into shape by the aid of massive corundum, which 

 is found in the country."! 



*See general Mineralogical case in the Museum for Atacamite, a Chloride 

 of Copper from the Desert of Atacama. 



t K. B. White, Journal Anthrop. Inst., Vol. 13, p. 247. 



