THE ANDEAN VALLEYS 37 



of the nineteenth century to find men reaching the 

 limits which nature has set to colonization, and mapping 

 out their domain. It is not until then that La Rioja 

 ceases to compete with Mendoza, or Catamarca with 

 Tucuman. While large industrial enterprises develop 

 at Mendoza and Tucuman, strong centres of urban 

 life arise, the population increases, and immigrants 

 stream in, the oases of the interior scarcely change. 

 Their population does not keep its level. Life has an 

 archaic character that one finds nowhere else in 

 Argentina. The physical conditions have retarded, 

 one would almost say crystallized, the economic develop- 

 ment. The living generation exploits the soil in ways 

 that to some extent go back as far as the indigenous 

 tribes, the masters of their Spanish conquerors in the 

 art of irrigation. The industry of fattening and con- 

 voying cattle, which was once the chief source of 

 wealth of the whole country, is still alive in those 

 districts. 



The zone of the elevated tablelands of the Andes 

 without drainage toward the sea — the Puna — has still, 

 below 22° S. latitude on the northern frontier of 

 Argentina, a width of about 250 miles. This breadth 

 steadily contracts southward as far as 28° S. latitude, 

 where the Puna ends about the level of the road from 

 Tinogasta to Copiapo. 



To the east and south of the Puna the Argentine 

 Andes are cut from north to south by a series of long 

 gullies and large basins, between which there are lofty 

 and massive chains with steep flanks. Some of these lie 

 in the heart of the mountains, while others often open 

 like gulfs upon the edge of the plain. These depressions 

 with rectilinear contours are a common feature of the 

 topography of the Andes in this latitude. The central 

 plain of Chile is closely related to them. In the 

 Argentine speech they are called valles : Valle de 

 Lerma, Valle Calchaqui, Valle de Iglesias, de Calingasta, 

 d'Uspallata. They are, however, not " valleys " in 



