﻿Eigenmann: Magdalena Basin 



23 



cross-range was an important feature in the drainage systems of this region, 

 and while it is certainly not so to-day, its presence adds but another feature to 

 the physiographic history of the Cauca River, which will some day be 

 unravelled. 



The Plains of Cali and Patia lie some 3,000 feet below the Plain of Popa- 

 yan, and the latter is therefore deeply trenched towards its northern and 

 southern borders by the streams which cross it on their way to these lower 

 levels. The Plain of Cali has suffered very little erosion. It is slightly con- 

 cave, sloping up to the mountains on either side, and between its southern 

 end, thirty miles south of Cali, and its northern limit, near Cartago, it has a 

 slope of about four feet per mile, and may be regarded as a plain between 

 3,000 and 3,500 feet above sea-level. The Cauca River flows through the 

 Cali Plain from end to end, and the levelness of the land, together with the 

 gentle rainfall and the healthy warm character of the region, have all com- 

 bined to cause it to be regarded as one of the garden spots of Colombia. 



North of Cartago the Cauca flows thru the knot formed by the 

 union of the Western and Central Cordilleras. In 110 miles., 

 between Cartago and Boca de Nechi it drops from an elevation 

 of 3,000 to 500 feet and forms, with the lower Magdalena, No. 4 

 of the above regions. 



The Magdalena descends rapidly from its sources to Neiva, 

 which has an elevation of 1,442 feet. From Neiva near 3° North it 

 descends more gradually to Girardot, at 1,056 feet, and Beltran 

 or Ambalema, 774 feet near 5° North. Between Beltran, Honda, 

 and La Dorado there are rapids where the river cuts its way out 

 from a trough in the Cordilleras of Bogota to the plain between 

 the Central Cordilleras and the Cordilleras of Bogota. This 

 lower Magdalena (below 600 feet) with the Cauca below Boca de 

 Nechi forms No. 4 in the present classification. No. 5, the Rio 

 Cesar, rises in the southeastern part of the Sierra Nevada de 

 Santa Mart a, flows a little west of south and empties into the 

 Magdalena at El Banco. It is the only stream in Colombia with 

 a southward flow that finally enters the Atlantic. 



The Fishes of the Magdalena Basin. In the lower 

 Magdalena (No. 4), collections have been made in the Cienega 

 near the mouth of the Magdalena, at Caceres on the Cauca, and 

 at Bodega Central for Steindachner and at Soplaviento, Calamar, 

 and at various places to Honda during my reconnaissance of 

 Colombia. It is from this part of the river that Humboldt 

 probably got his notes of the fishes mentioned in Recueil d 7 

 Observation de Zodlogie et Anatomie. Nothing is known from the 

 Rio Cesar. In the Upper Magdalena the only collection was made 

 at Girardot. In the Upper Cauca I collected in the Plains of 



