TRANS-ANDEAN ROUTES 147 



south of the volcano Lanin. That is the beginning 

 of the glacial valleys which go to the heart of the 

 Cordillera, some of them crossing the mountains from 

 east to west. They have not yet been entirely explored. 

 The Bariloche pass, south of the Tronador, by which 

 the Chilean missionaries reached Nahuel Huapi in 

 the eighteenth century, is no longer used. The Cajon 

 Negro pass, west of Lake Traful, through which Bailey 

 Willis traces the line of a southern trans-Andean 

 railway, was only recently discovered, and the valleys 

 which run into it on the Chilean side are not yet well 

 known. The two best-known trans-Andean routes 

 to-day are the Perez Rosales road, which leads from 

 Chile to Nahuel Huapi by the north of the Tronador, 

 and further north, the road from Lake Lacar to San 

 Martin. Both these have received some attention, 

 and the lakes are connected by telegraph or telephone. 

 The frequent need to unload and reload makes the 

 traffic costly, but it is permanent and is not interrupted 

 in winter. The reduction of the export of cattle to 

 Chile has cut down the traffic for a time, but it is sure 

 to recover. The permanent importance of it is one of 

 the facts most clearly written by nature upon the soil 

 of South America. 



It is not easy, in the absence of documents, to attempt 

 to give for Patagonia as a whole a detailed description 

 of the pastoral industry, and to follow step by step 

 on the spot its efforts to adjust itself to the natural 

 conditions. But the analysis may be attempted in 

 regard to the region between San Antonio and Lake 

 Nahuel Huapi south of the Rio Negro, ^ the valley 

 of the Rio Negro, and the tableland which stretches 

 westward between the Neuquen and the Limay. This 

 part of Patagonia is now easily accessible, and it is 

 entered by two parallel railways. One starts from 



' This was the area studied by the Commission of which Bailey 

 WilUs was chairman. 



