HYDEOGEAPHY OF PEEU. 289 



headlands detached from the inaiuland by erosion. South of the promontories 

 terminating in the Punta Parina and Punta Aguja caj)es the surface is studded 

 with the two little insular groups of Lobos de Tierra and Lobos de Afuera. 

 These are followed by others lying nearer to the shore, such as the Guailape, 

 Huaura, Pescadores d'Ancon, San Lorenzo, and Hormigas de Afuera clusters, and 

 lastly the Chinchas, so important before the exhaustion of their rich guano- 

 beds, but now valueless except for the shelter they offer to the harbour of 

 Pisco. The other reefs fringing the coast farther south also contained similar 

 deposits, some of which are still worked. Some 210 miles off Punta Aguja an 

 island is reported to have recently appeared above the surface, but the state- 

 ment awaits confirmation. 



III. 



Rivers — The Santa and other Pacific Streams. 



In their hydrographie aspect the two slopes of Peru present a striking 

 contrast, entirely due to the climate — on one side feeble watercourses, usually dry 

 in their lower reaches, on the other a superabundance of running waters descend- 

 ing through various channels to the mighty Amazons. In the extreme north 

 the Achira, fed by numerous torrents from the Loja heights, still reaches the sea 

 in an exhausted state ; but the Rio Piura, which follows next southwards, is 

 entirely lost in the riverine plantations and the sands of the lower plains. Other 

 quebradas, or river gorges, occur on the outer sIojdc of the Cordillera ; but none 

 are perennial except the Santa, which differs from most other Peruvian coast 

 streams in that it rises, not on the western slopes, but in a longitudinal valley in 

 the very heart of the Andes. 



After escaping from the Aguach lagoon (13,850 feet), the Santa is joined by 

 the emissary of the still larger Cono-cocha basin (12,930 feet), the united currents 

 flowing from south-east to north-west along the bed of an enormous fissure 

 dominated by both parallel ranges. At the foot of the Andean giants, Hualcan, 

 Huascan, and Huandoy, the Santa receives several contributions from the eastern 

 plateau, rising close to the headwaters of the Amazon, and forcing their way in 

 deep ravines through the Western Cordillera. After its junction with the Rio de 

 Manta, one of these torrents from the plateau, the mainstream turns westwards to 

 the gorge through which it escapes seawards. Beyond the gorge it occasionally 

 discharges an enormous volume, so that during the floods it is difficult to cross, 

 and presents great obstacles to traffic on the plains. The Santa is at times joined 

 just above its mouth by the intermittent Lacramarca coast stream. 



The Rimac, another of these coast streams, owes its celebrity to the city which 



it traverses, and which bears the same name under the modified form of Lima, that 



is, the " Speaker," in reference to a temple on its banks famous for its oracles. 



The Rimac rises in the Sierra at the Antarangra Pass (15,600 feet), within thirty 



20 



