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.
South of the Bermejo the land is more elevated and drier, though large depressions covered with marshy lagoons are to be found, similar to those farther north.
The water-courses and depressions of the shingly steppes afford pasturage sufficient for the guanaco, and in places support a thorny vegetation of low growth and starved appearance.
Lake Torrens, the largest of these depressions, sometimes forms a sheet of water 100 m.
The cells belonging to any given thread may be recognized at an early stage of growth, because each cell is connected with its neighbors belonging to the same thread by two depressions or pits, one at each end.