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 of the officials who called on us, and talked with a most intelli- gent schoolmaster from southern Chile. ‘The town ts but little disturbed by the government taxgatherers; and in the worst years, as when the stream dwindles or the dam breaks and ruins both fields and crops, taxes are remitted altogether.

From each oasis on the desert border a trail climbs the cor- dilleran slopes. In places it follows the stream bed. In other places it runs along the flat interfluves or climbs perilously along the steep side of a deep ravine. In some cases two trails are in use, as in the case of the Quebrada de Tarapacé between Mocha and Sebaya, where the valley trail is impassable during the flood season when sudden deluges fill the narrow passage of the gorge. More commonly this duplication of trails is a fea- ture of the Eastern Cordillera, where heavy rains each year make it necessary to have a dry-weather and a wet-weather trail. The wet-weather trail follows high ground and has a roundabout and longer course and steep gradients. It might be called an emergency trail and in most cases is abandoned as soon as a road of any pretensions has been built with bridges or improved fords that enable the graded valley trail to be used practically the whole year round. i

I have spoken of the lower edge of the belt of grass that lies like a band across the western face of the mountains. It has also an upper edge where the short and nutritious grasses give way to the bunch grass, or tchu grass as it is called, and ground mosses and resinous shrubs such as the fola bush. ‘The grass is in the temperate zone of the mountain flank; the mosses and resinous shrubs are in the alpine zone. High up on the plateau summits at 13,000 fect we were surprised to find the large and straight-stemmed cactus {cardén) where there are nightly frosts for at least six weeks of the year during late May, June, and early July. This general type of cactus is known in our Southwest but cannot endure frost there. The belt of grass be- tween 8000 feet and 10,000 feet extends all the way from Peru, where I crossed it in 1911 on the 73rd meridian, southward