573 



speaking, according to one great division of the 

 surface of South America in those basins, we 

 have called the basin of the Rio Negro and the 

 Amazon. The low regions, which are bounded 

 by the southern and northern declivities of the 

 mountains of Pari me and Brazil, and which 

 the geologist ought to mark by one name, con- 

 tain, according to the no less precise language 

 of hydrography, two basins of rivers, those of 

 the Upper Oroonoko and the Amazon, sepa- 

 rated by a ridge (indication of al ternating slopes), 

 that runs from Javita towards Esmeralda. From 

 these considerations it results, that a geological 

 basin (sit venia verbo) may have several reci- 

 pients, several emissaries, divided by small 

 ridges almost imperceptible, and may contain 

 at the same time the waters that go to the sea 

 by different furrows independent of each other, 

 and the systems of inland rivers flowing into 

 lakes more or less charged with saline matter. 

 A basin of a river, or hydrographic basin, has 

 but one recipient, one emissary ; if, by a bifur- 

 cation, it gives a part of its waters to another 

 hydrographic basin, it is because the bed of the 

 river, or the principal recipient, draws so near 

 the banks of the basin or the ridge of partition 

 that the ridge crosses it in part. 



The distribution of the inequalities of the sur- 

 face of the globe does not display any limits 

 strongly marked between the mountainous coun- 



