580 



AMAZONIA AND LA PLATA. 



Tunuyan, continues to flow southwards. But the sluggish current is frequently 

 dammed and even displaced by the shifting sands and high dunes drifting before 

 the wind on these nearly horizontal plains. The river, which here takes the 



Fig. 154. — Ancient Basin of the Colorado. 

 Scale 1 : 13,000,000. 



Depths. 



0to5 

 Fathoms. 



m 



5 to 10 

 Fathoms. 



10 to 25 

 Fathoms. 



25 Fathoms 

 and upward.s. 



. .-ÎIO Miles. 



fully justified name of Salado, wanders, so to siiy, under the action of the aerial 

 currents. 



The Diamante, one of its affluents, which is stated to be to some extent 

 navigable, has also shifted its channel under the same influences. Formerly 



