These minor ranges, excepting the Zenta, are separated from the Andean masses by comparatively low depressions and are usually described as distinct ranges; topographically, however, they seem to form a continuation of the ranges running southward from the Santa Victoria and forming the eastern rampart of the great central plateau of which the Puna de Atacama covers a large part.
Above sea-level, where it is crossed by a railway; north-east is another extensive saline basin enclosing the " Mar Chiquita " (of Cordoba) and the morasses into which the waters of the Rio Saladillo disappear; and on the north are the more elevated plains, partly saline, of western Cordoba, which separate this isolated group of mountains from the Andean spurs of Rioja and San Luis.
Some of the principal affluents are the Vinchina and Jachal, or Zanjon, which flow into the Vermejo, the Patos, which flows into the San Juan, and the Mendoza, Tunuyan and Diamante which flow into the Desaguadero, all of these being Andean snow-fed rivers.
In the extreme north-west an elevated region, whose aridity is caused by the " blanketing " influence of the eastern Andean ranges, extends.
Below this region, where the Andean barrier is low and broken, the moist westerly winds sweep over the land freely and give it a large rainfall, good pastures and a vigorous forest growth.