458 



ZONES AND REGIONS [Pt. Ill, Sect. II 



TUCUMAN. 



SALTA. 



26°5o'S., 430 meters 24°46'S.,65"24'W.,i,200 

 above sea-level. meters above sea-level. 



I 



Further soutli the annual rainfall, except at isolated spots, sinks below 

 100 cm. The eastern half of Argentina has at most 70-100 cm. of rain- 

 fall ; in the west the precipitations are less, they sink to 20 cm. and even 

 fewer, and the country assumes a desert character (the xvestcrn monte of 

 Lorentz). 



The eastern parts of Uruguay and Argentina, that lie nearer to the 

 Atlantic, have an annual rainfall mostly as high as 70-100 cm., and are clad 

 with pure steppe (pampa). West of the pampas there stretches as far as 

 the Cordilleras, an extensive district of thorn-woodland with a rainfall de- 

 creasing to the west ; this is the vioute-foniiatioii of Lorentz, cspinal-fonna- 

 tion of Hieronymus. This woodland district is subdivided into a subdistrict 

 relatively rich in precipitations, the eastern inontc of Lorentz, with about 

 40-70 cm. rainfall, and another, poor in precipitations, that to a great 

 extent may be described as desert. The rainfall ranges from less than 

 20 cm. at the base of the Andes (Pilciao 13 cm., San Juan 7 cm.) to about 

 40 cm. on the borders of the eastern monte. 



Many explorers have been surprised that the eastern humid district should 

 produce only grass, but the drier western one woods. They did not know 

 the difference between a grassland- and a woodland-climate, nor how grass 



