26o NORTHERN CHILE. [CHAP. xvi. 



at the bottom of the flat broad valley. There was no water nearer 

 than three or four leagues, and that only in very small quantity, and 

 bad : the soil was absolutely sterile ; I looked in vain even for a lichen 

 adhering to the rocks. At the present day, with the advantage of 

 beasts of burden, a mine, unless it were very rich, could scarcely be 

 worked here with profit. Yet the Indians formerly chose it as a 

 place of residence! If at the present" time two or three showers of 

 rain were to fall annually, instead of one, as now is the case, during as 

 many years, a small rill of water would probably be formed in this 

 great valley ; and then, by irrigation (which was formerly so well 

 understood by the Indians), the soil would easily be rendered sufficiently 

 productive to support a few families. 



I have convincing proofs that this part of the continent of South 

 America has been elevated near the coast at least from 400 to 500, and 

 in some parts from 1,000 to 1,300 feet, since the epoch of existing shells ; 

 and further inland the rise possibly may have been greater. As the 

 peculiarly arid character of the climate is evidently a consequence of 

 the height of the Cordillera, we may feel almost sure that before the 

 later elevations, the atmosphere could not have been so completely 

 drained of its moisture as it now is ; and as the rise has been gradual, 

 so would have been the change in climate. On this notion of a change 

 of climate since the buildings were inhabited, the ruins must be o 

 extreme antiquity, but I do not think then- preservation under the 

 Chilian climate any great difficulty. We must also admit on thij 

 notion (and this perhaps is a greater difficulty), that man has inhabited 

 South America for an immensely long period, inasmuch as any change 

 of climate effected by the elevation of the land must have been extremely 

 gradual. At Valparaiso, within the last two hundred and twenty years, 

 the rise has been somewhat less than nineteen feet : at Lima a sea-beach 

 has certainly been upheaved from eighty to ninety feet, within the Indio- 

 human period : but such small elevations could have had little power 

 in deflecting the moisture-bringing atmospheric currents. Dr. Lund, 

 however, found human skeletons in the caves of Brazil, the appearance 

 of which induced him to believe that the Indian race has existed during 

 a vast lapse of time in South America. 



When at Lima, I conversed on these subjects* with Mr. Gill, a civil 

 engineer, who had seen much of the interior country. He told me 

 that a conjecture of a change of climate had sometimes crossed his 

 mind ; but that he thought that the greater portion of land, now 

 incapable of cultivation, but covered with Indian ruins, had been 

 reduced to this state by the water-conduits, which the Indians formerly 

 constructed on so wonderful a scale, having been injured by neglect 

 and by subterranean movements. I may here mention, that the 



* Temple, in his travels through Upper Peru, or Bolivia, in go:ng from 

 Potosi to Oruro, says, " I saw many Indian villages or dwellings in ruins, 

 up even to the very tops of the mountains, attesting a former population 

 where now all is desolate." He makes similar remarks in another place; 

 but I cannot tell whether this desolation has been caused by a want of popu- 

 lation, or by an altered condition of the land. 



