572 



noko and the Amazon. The views of the geo- 

 logist are not identical with those of hydrogra- 

 phy. In the basin which we have called that 

 of the Rio de la Plata and Patagonia, the waters 

 that follow the lines of the greatest declivities 

 have many issues. The same basin contains 

 several vallies of rivers ; and when we examine 

 nearly the polyedric surface of the Pampas and 

 the portion of their waters which^ like the 

 waters of the steppes of Asia *, do not go to 

 the sea, we conceive that these plains are di- 

 vided by small ridges or lines of elevation, and 

 have alternating slopes inclined, with respect 

 to the horizon, in opposite directions. In order 

 to point out more clearly the difference be- 

 tween geological and hydrographic views, and 

 prove that in the former, abstracting the 

 course of the waters which meet in one reci- 

 pient, we obtain a far more general point of 

 view, I shall here again recur to the hydrogra- 

 phic basin of the Oroonoko. That immense 

 river rises on the southern slope of the Sierra 

 Parime ; it is bounded by plains on the left bank, 

 from the Cassiquiare to the mouth of the Ata- 

 bapo, and flows in a basin which geologically 



* The German geographers mark by the name of rivers 

 of the steppes (steppenftusse) every system of running waters 

 which has its maximum of depression in an interior lake. 

 See above, Vol. iv, p. 149. 



* Journal de VEcole poly technique, Vol. vii, p. 265. 



