THE EIO OATJCA. 



155 



walls, across which bridges of trailing plants have been thrown, Indian fashion. 

 One of these, on the route between Medellin and Antioquia, is no less than 750 

 feet long from bank to bank. 



Beyond the last escarpments the Cauca is joined by the Nechi, a considerable 

 affluent descending from the heart of the Central Cordillera, in nearly a straight 

 line from south-west to north-east, thus forming, as it were, a chord to the arc 

 described by the mainstream itself. The Nechi is formed by two briinches, the 

 smaller of which keeps the name of the mainstream, although flowing in a lateral 



Fig. 59.- Mouths of the Magdalena. 

 Scale 1 : 1,600,OUO. 



ïf^^ --SA^'TAMAR■r.^■, 



West op Greenwich 



0to50 

 Fathoms. 



Depths. 



50 to 500 

 Pathoms. 



5(10 Fathoms 

 and upwards. 



30 Miles. 



valley, while the longer and more copious, which retains the direction of the lower 

 course, is known as the Force or Medellin. Both descend from the highlands 

 abruptly to the plains through a series of terraces, cascades, and rapids, like those 

 of the Sogamoso. The Gruadalupe affluent of the Force plunges over a salto (fall) 

 no less than 820 feet high. 



At the Nechi confluence the Cauca, here 2,000 feet wide, winds throuo-h a 

 level plain between low banks fringed with marshes. At Guamal, where it joins 

 the Magdalena, it has a discharge of 77,800 cubic "set per second, and seems little 

 inferior in volume to the mainstream. After the junction of the San Jorge, and 



