Every one must have remarked how mud-banks, left by the retiring tide, imitate in miniature a country with hill and dale; and here we have the original model in rock, formed as the continent rose during the secular retirement of the ocean, instead of during the ebbing and flowing of the tides.

If a shower of rain falls on the mud-bank, when left dry, it deepens the already-formed shallow lines of excavation; and so it is with the rain of successive centuries on the bank of rock and soil, which we call a continent.
We rode on after it was dark, till we reached a side ravine with a small well, called "Agua amarga." The water deserved its name, for besides being saline it was most offensively putrid and bitter; so that we could not force ourselves to drink either tea or mate.

I suppose the distance from the river of Copiapo to this spot was at least twenty-five or thirty English miles; in the whole space there was not a single drop of water, the country deserving the name of desert in the strictest sense.

Yet about half-way we passed some old Indian ruins near Punta Gorda: I noticed also in front of some of the valleys which branch off from the Despoblado, two piles of stones placed a little way apart, and directed so as to point up the mouths of these small valleys.

My companions knew nothing about them, and only answered my queries by their imperturbable "quien sabe ?" I observed Indian ruins in several parts of the Cordillera: the most perfect which I saw were the Ruinas de Tambillos in the Uspallata Pass.