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 a more intensive agriculture is practiced with irrigation, Those streams that have their chief tributaries in the forest belt are most constant in flow and furnish to the population

. 97—Desert growth on the dry, gravelly floor of the Catchaquí valley northeast of Cachi, elevation 8500 feet. Beyond the candelabra type of cactus in the foreground may be seen the more common columnar type, the wood of which is shown in detail in Figure 98.

groups on the mountain border the means for agriculture and stock raising on a large scale.

West of Rosario de Lerma (Fig. 95) the woodland begins almost at the border of the plain, clouds hanging over the head of the lower secondary ranges almost constantly winter and summer. Traveling up the Escoipe ravine one enters a zone