HASEMAW, GEOGRAPHICAL DI8TRIB UTION IN SOUTH AMERICA 37 



-of the reversal of Eio Amazonas, but inasmuch as the most of it is not 

 sufficiently decisive to account for such a momentous geological change, 

 it has been omitted ; for such data may be said to harmonize equally well 

 with any view of the region in question. 



Finally, in reference to the time of the reversal of Eio Amazonas, I 

 may restate that Katzer has placed it in the Miocene. It appears that 

 it could not have been before that epoch, but until the exact age of the 

 '"East Andean fossils" has been determined, we cannot settle this most 

 important question with any degree of certainty. The determination of 

 the exact age of the fossils from Alto Amazonas and the exact location 

 •of the exit of the East Andean Sea offer alluring opportunities for future 

 exploration. 



STEEAM PIRACY 



On the divides between various South American rivers, the headwater 

 streams sometimes approach one another with closest intervals. This is 

 particularly true of the divides on the Piano Alto. For example : Eios 

 Sao Marcos and Bartholmeo of Eio Parana; Eios Bezzero, Jardin and 

 Preto of Eio Paracatii and Eio Urucupa, both of which flow into Eio 

 Sao Francisco, and Eio Parana, an affluent of Eio Tocantins. All of 

 these rivers flow from brejos (swamps or sloughs), Lagoa Feia and 

 •other highland lagoons between the villages of Paracatu and Formosa of 

 southeastern Goyaz. In fact, these headwaters of three large river basins 

 rise in sight of each other from brejos which vary from 1100 to 1147 

 meters of altitude, and the maximum altitudes of the intervening sand 

 hills are never more than 1177 meters. 19 



Stream piracy (coalescence of streams) may have existed on a very 

 limited scale between the following rivers — at any rate, their headwaters 

 are rjot far apart: 



1. Eio Eibeira de Iguape ( ? robbed Eio Capella) and Eio Paranapo- 

 nema. 



2. Eios Sao Francisco and Doce and Eio Grande of the Parana near 

 Carandahy and Miguel Burnier, Minas Geraes. 



3. Eio Parahyba and Eio Tiete, Eio Parahyba having robbed its 

 headwaters flowing south from Eio Tiete. 



4. Eios Aragua}r, Xingu and Tapajos and Eio Paraguay. 



5. Eio Ibicuhy of Eio Uruguay and Eio Vaccachy of Eio Grande do 

 Sul. 



10 The highland fauna and flora certainly interchange between these three river basins, 

 but the typical Amazonian, Sao Franciscan and Paranean fauna and flora are at least 

 one hundred miles away from this headwater region, i. e., at a much lower altitude. 



