sites of the Andes. In addition to the principal trails that cross the Puna from one side to the other there are many other trails or traces that connect interior points.
By one or another of the three main trails and the tributa- ries which run to places of secondary importance every settle- ment has its connection with places both near by and distant; and, though the routes to be traveled may be long and diffi- cult, time is of little importance, the cost of forage is small, and an exchange of products makes life possible no matter how isolated the spot or how distant from the larger towns of the fertile borderlands. “Vhe permanence of the trails of the Andes is natural when we consider the difficulties of so broken a passage. The commerce has varied exceedingly; but the route, the type of carriage, and the social and economic struc- tures that are served by the mountain trail have been little changed.
In the tropical forest a trail may be overgrown with jungle if it is abandoned for only a few years. The muleteers carry machetes, long-handled knives, with which they constantly snip off the ends of intruding branches and undergrowth. In desert country it is the signes del camino, or signs of the way (trail markers one might call them), that are kept in repair. As already deseribed these are rough piles of stone or may be recessed chambers and even mortared structures or may be nothing more than little wooden crosses such as are used to mark the graves. Again, the trail marker may be a huge cross or a tower light. Thus while in a few vears a trail in the forest may be choked and even forgotten, a trail in the desert re- mains a trail even if there is passage over it only at intervals of several years. The trail remains a fixed feature in communica- tion from settlement to settlement The Inca road through the Desert of Atacama is said to be traceable over many leagues (ef. p. 103). The trails of the mountains and of the coastal desert of the Central Andes have therefore had a continuous record of use and have acquired a historical importance out of proportion to most trails in the rest of South America. When the settler comes the trails become roads or all trace of them disappears, and when new ranches are laid out new needs
