Todd-Carriker : Birds of Santa Marta Region^ Colombia. 9 



flowing southwestward through a broad belt of forest and savanna. 

 The Rio Ariguani, its last and largest tributary, springs from Mount 

 Chinchicua, at the end of the southern spur of the Sierra Nevada, and 

 curves around the outlying mountain mass lying off to the southward. 



The rivers of the main western slope of the Sierra Nevada all drain 

 into the Cienaga Grande, a large lake of brackish water, which is a 

 part of the delta system of the Magdalena. There are a number of 

 streams descending this slope, which combine into two main rivers, 

 the Rio Frio and Rio Aracataca, before iinally reaching the Cienaga. 

 Little is known about the upper reaches of these rivers, beyond the 

 fact that the Aracataca has its source in the region south of the Snow 

 Peaks, while their lower courses are through impenetrable forest. 



The streams on the northwest and north sides of the San Lorenzo 

 and the Sierra Nevada proper, .where the slopes are more precipitous, 

 are much shorter in general than those coming down the southern and 

 western slopes. The Rio Manzanares, which takes its rise on the 

 north slopes of the Horqueta, and flows down to the sea at Santa 

 Marta through a well-wooded valley, where are located a number of 

 small towns and villages, is one of the best known. The Rio Gaira, 

 which is larger even than the Manzanares, receives nearly all its 

 water from the San Lorenzo, .falling down from its source in a long 

 series of cascades to reach the sea near the town of Gaira. On the 

 north slopes of the Sierra Nevada there are not less than six streams 

 of considerable importance between Santa Marta and Rio Hacha. 

 The first of these, the Rio Piedras, drains the eastern slopes of the 

 Horqueta and San Lorenzo, and enters the Caribbean at the point 

 where the humid forest first descends to the coast. Then follow the 

 Mendiguaca, Buritaca, Don Diego, Palomina, and Ancha, of which the 

 last three are known to have their sources in the snow-fields of the 

 Sierra Nevada. Of these the best known is the Rio Ancha, which 

 take its rise to the northeast of the Snow Peaks, and which the trail 

 follows in making the ascent from this side. Considerably beyond 

 this again is the Rio Rancheria, which drains the southern slopes of 

 the Sierra Nevada in part, curving around their eastern flank to flow 

 into the sea near Rio Hacha. The valleys of the Rio Cesar and Rio 

 Rancheria are practically conterminous, so that a depression of less 

 than a thousand feet would suffice to isolate the Sierra Nevada com- 

 pletely from the South American continent. 



