HYDEOGRAPHY OF SOUTH AMERICA. 



between tlie two fluvial systems, either by a series of portages, or by cutting a 

 canal four or five miles long across the divide. Other interminglings of river 

 basins have also been developed farther east between the eastern affluents of 

 the Paraguay and the Arinos, a main branch of the Amazonian Tapajoz, and 

 attempts to connect them by cuttings were made in the years 1713 and 1845. 



Fig. 2. — Inhabitable Regions in South Ameeica. 

 Scale 1 : 70,000,000. 



Arid deserts. 



Morasses. 



Glacial zones. 

 . 930 Miles. 



Inhabitable lands. 



Viewed as a whole, the South American hydrographie system is remarkable 

 for the prodigious volumes which are carried seawards by the main arteries, and 

 much of which expands in the interior, not into deep lacustrine depressions, but 

 in lateral backwaters and labyrinths of temporary channels, varying from year to 

 year, and from season to season, with the periodical flooding and subsidence of 

 the main streams. 



