248 THE RIVER-ROUTES 



channel for a time from the cliff. These curves seem, 

 as a rule, to coincide with the confluence of rivers, 

 which bring a heavy load of clay from the tableland ; 

 as, does, for instance, the San Feliciano, north of 

 Hernandarias. They are marked by shallows, in 

 strong contrast to the great depths of the straight 

 sections. The San Feliciano paso, which is twelve 

 feet broad to-day, was only six feet broad in 1908. 

 It appeared on Sullivan's map in 1847.^ 



Below Parana, as far as the estuary, the careful 

 observations that have been made since 1903 on the 

 movement of the river have enabled us to learn some 

 of its laws. 2 We can distinguish four sections of 

 unequal length. From Parana to Diamante the river 

 remains in touch with the cliffs of the left bank. It is 

 not straight ; it describes a series of linked crescents 

 of equal radius, which seem to be traces of so many 

 meanders. Only one in two of the windings of the 

 cliff is followed by the channel. The wandering of the 

 river is confined within limits as in a fixed mould. 

 The Paracao shallow, which for a long time pre- 

 vented ships from reaching Santa Fe (gradually 

 deepened by dredging from eight to nineteen feet 

 between 1907 and 1911) is at the angle where two 

 of these curves meet. On the right bank the secondary 

 arms continue to follow the river (Parana viejo, 

 Riacho de Coronda).3 



' A little above its actual position. 



» In studying the variations of tlie bed of the Parani it is necessary 

 to avoid comparing maps drawn at dates separated by long intervals. 

 The differences of such maps are such that they do not enable us to 

 follow the processes by which the actual forms have been derived 

 from earlier forms. The analogies which they show are sometimes 

 due, not to the permanence of the topography, but to the return of 

 a complete cycle of changes, or of conditions analogous to the earlier 

 conditions. 



3 The secondary arms of the right bank, north of Santa Fe, were 

 not explored until 1870. Sullivan's map (1847) only mentions the 

 Riacho de San Jeronimo, which is visible for a short distance below 

 20° S. lat. The right bank was the domain of the Indians, and the 

 Correntinos would not venture near it. In 1870 ships began to use 



