April, 1835. INDIAN RUINS. 411 



at the bottom of a 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 

 there 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 during 

 as many years, as now is the case, a small rill of water 

 would in all probability be formed in this great valley, 

 draining a mountainous country; and then, by irrigation 

 (the method of which was formerly so well understood by 

 the Indians), the soil might easdy be rendered sufficiently 

 productive to support a few famiUes. 



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

 America has been elevated, near the coast, at least from four 

 to five hundred feet, since the epoch of existing shells ; and 

 further inland the rise possibly may have been greater. As 

 the peculiarly arid character of the chmate is evidently a 

 consequence of the height of the great range of mountains, 

 we may feel almost sure, that prior to the latter elevations, 

 the atmosphere was not so completely drained of its moisture 

 as at the present day. At a remote geological era, it is 

 probable that the Andes consisted of a chain of islands, 

 which were covered by luxuriant forests ; and many of the 

 trees, in a silicified state, may now be seen embedded in 

 the upper conglomerates. Of these I measured one which 

 was cylindrical, with a circumference of fifteen feet. As it 

 is nearly certain that the mountains have risen slowly, so 

 would the chmate likewise become deteriorated slowly. 

 We need not feel greatly surprised at walls of stone and 

 hardened mud here lasting for many ages, when we remember 

 how many centuries the Druidical mounds have withstood 

 even the chmate of England. The only question is, whether 

 the amount of change, since the introduction of man into 

 South America, has been suflicient to cause a sensible 



