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 gives to a self-contained oasis is always terrific and sometimes fatal. I saw the irrigation works at the site of the now deserted village of Algarrobal. Here and there a neglected orchard tree or pepper bush, struggling along as best it can without irrigation, or the crumbling mud walls of some abandoned home are a mournful testimony to the ruin wrought by the flood in this once happy valley. The fragment of people now

. 22—The chañar seed, or nut, in natural size. The outer covering is tough and hard but somewhat flexible. The white inner substance while dry and hard can be cut with a knife. Ground up, it is used as an in- gredient for soup and to make so-called chañar bread (compare Fig. 21).

living within sight of the former more populous valley occupies a safer position. The tiny oasis of Chacarilla is perched high above reach of flood upon the slopes of a terraced alluvial fan, whose outer edge is protected by a stone wall. The small spring-fed stream discharging across the fan is Jed out upon the gardens and orchards by half a hundred diverting canals.

Apart from the vicissitudes duc to such sweeping disasters the amount of Jand that can be put under cultivation varies much from year to year. In times of serious drought lands ordinarily habitable have to be entirely abandoned for the