392 ANNUAL EEPOKT SMITHSONIAN INSTITUTION, 1908. 



In this region, as in general in every considerable widenings of the 

 Cordillera, the grouped summits do not follow the principal axes in 

 uniform and parallel directions, and he remarked that the general 

 disposition of the Andes in this latitude is well worth the attention 

 of geologists. From where the Cordilleras unite in the knot of Cuzco 

 (Vilcanota) their direction is N. 80° W. He calls attention to the 

 fact that the direction of the coast follows these changes, and remarks 

 that the parallelism between the coast and the Cordilleras of the 

 Andes is a phenomenon the more worthy of attention as it occurs in 

 several parts of the globe where the mountains do not in the same 

 manner form the shore. 



Description by Raimondi. 



It is to be regretted that Raimondi did not publish a description of 

 the Andes. However, his writings contain much information, and 

 in his edited notes published in the chapter "Apuntes Orograficos," 

 in Volume IV of El Peru there is a partial description of the 

 Cordilleras. He adopted the nomenclature of Humboldt. The 

 Andes is used as a general term for the whole mountain system, 

 and the various branches are spoken of as " Cordilleras." The 

 branch to the east of Lake Titicaca he called the " Cordillera Ori- 

 ental " and the one to the w^est the " Cordillera Occidental." The 

 union of these branches to the north of Lake Titicaca he calls the 

 " Knot of Vilcanota," taking the name from a snow-capped peak. 

 From this knot northward he recognized three branches instead of 

 the two somewhat vaguely described by Humboldt. The Cordillera 

 Occidental follows the direction of the coast. The Cordillera Cen- 

 tral separates the valleys of the Apurimac and the Vilcanota or 

 Urubamba rivers, while the Cordillera Oriental separates the inter- 

 Andean region from the forest region of the interior. These three 

 Cordilleras unite in the Knot of Cerro de Pasco, from which point 

 northward three branches diverge. The Cordillera Occidental for a 

 portion of its way is divided into two, the western of which is known 

 as the "Cordillera Negra " (Black Cordillera) and the eastern or 

 main one takes in that region the name " Cordillera Blanca " (White 

 Cordillera) because of its snow-covered peaks. The Cordillera Cen- 

 tral separates the Maranon and Huallaga rivers, while the Cordillera 

 Oriental separates the Huallaga from the Pachitea and Ucayali. 

 The Cordillera Central describes a curve, and is cut by the Maranon 

 at the falls of Manseriche. The Cordillera Oriental lowers, and is cut 

 by the Huallaga at the Falls of Aguirre and then runs in a north- 

 west direction and joins the Cordillera Central. Humboldt states 

 that it dies out in latitude 6° 15'. With this exception, it will be seen 

 that in the northern part of Peru the description by Raimondi does 



