PLAINS OF THE AMAZON. 863 



Parapiti, which lower down takes the names of Eio San 

 Miguel and Eio Sara. The savannahs of the province of 

 Chiquitos communicate on the north with those of Moxos, 

 aud on the south with those of Chaco ; but a ridge or line of 

 partition of the waters is formed by the intersection of two 

 gently sloping plains. This ridge takes its origin on the 

 north of La Plata (Chuquisaca) between the sources of the 

 Guapaix and the Cachimayo, and it ascends from the parallel 

 of 20 to that of 15J south latitude, consequently on the 

 north-east, towards the isthmus of Villabella. From this 

 point, one of the most important of the whole hydrography 

 of America, we may follow the line of the partition of the 

 water to the Cordillera of the shore (Serra do Mar). It is 

 seen winding (lat. 17-20) between the northern sources of 

 the Araguay, the Maranhao or Tocantines, the Kio San Fran- 

 cisco, and the southern sources of the Parana. This second 

 line of partition which enters the group of the Brazil moun- 

 tains, on the frontier of Capitania of Goyaz, separates the 

 flowings of the basin of the Amazon from those of the Eio de 

 la Plata, and corresponds, south of the equator, with the line 

 we have indicated in the northern hemisphere (lat. 2-4), 

 on the limits of the basins of the Amazon and the Lower 

 Orinoco. 



If the plains of the Amazon (taking that denomination in 

 the geognostic sense we have given it) are in general distin- 

 guished from the Llanos of Venezuela and the Pampas of 

 Buenos Ayres, by the extent and thickness of their forests, 

 we are the more struck by the continuity of the savannahs in 

 that part running from south to north. It would seem as 

 though this sea of verdure stretched forth an arm from the 

 basin of Buenos Ayres, by the Llanos of Tucuman, Manso, 

 Chuco, the Chiquitos, and the Moxos, to the Pampas del 

 Sacramento, and the savannahs of Napo, Guaviare, Meta, 

 and Apure. This arm crosses, between 7 and 3 south 

 latitude, the basin of the forests of the Amazon ; and the ab- 

 sence of trees on so great an extent of territory, together 

 with the preponderance which the small monocotyledonoua 

 plants have acquired, is a phenomenon of the geography of 

 plants which belongs perhaps to the action of ancient pelagic 

 currents, or other partial revolutions of our planet. 



