294 



SOUTH AMERICA— THE ANDES EEGIONS. 



it reverses its course as far as another fissure, through which it pierces the eastern 

 range east of Huancayo. 



Beyond the mountains the Acobamba takes the name of Mantaro, and at 

 Pisquitini joins the right bank of the Apuriraac, the " Boisterous," which also 

 flows in a longitudinal valley parallel with the Andean escarpments, and which 

 is joined by the Pampas and other tributaries descending in abrupt windings and 

 deep gorges between the mountains and plateaux. Below the confluence the 

 united waters of the Mantaro and Apurimac become the Ene or Eni, that is, 

 " Great Piver " in the Campa language. 



On the plains the Ene is joined by the Perene, which, although only one of the 



Fig. 114. — Maeanon and Ucatali Confluence. 

 Scale 1 : 1,600,000. 



74-° 10' J West oF Greenwich 



75° lo- 



se Miles. 



secondary streams of the basin, is perhaps the most important from the economic 

 point of view ; its valley forms a prolongation of the road between Lima and the 

 plateau, while its lower course, navigable for a distance of eome 12 miles, offers 

 the shortest route to the Amazons. After its junction with the Perene the Ene 

 takes the name of Tambo, which beyond a last spur of the mountains intermingles 

 its waters with the Quillabamba to form the great Pio TJcayali. 



The Quillabamba, flowing in a line with the lower valley, may be regarded as 

 the main upper branch of the system. Its chief affluents, the Paucartambo and 

 the Urubamba, the latter rising at the Paya Pass, are also disposed in the 



