362 SOUTH AMERICA— THE ANDES EEGIONS. 



even within the historic period. Thus five islets near Puno are now connected 

 with the mainland, and the exposed surface is strewn with freshwater shells. The 

 west coast which slopes very gently, is studded with lagoons and swamps traversed 

 by causeways dating from pre-Columbian times. In fact, the lake is so shallow 

 alono" the western margin that a further subsidence even of 10 feet would suffice 

 to reduce its whole area by at least one-fifth.* 



Viewed as a whole the lake would present the form of an elongated oval but 

 for a chain of hills revealed by a line of emerged summits, and disposed in the 

 direction of the main axis parallel with both shores. Thus have been upraised the 

 southern peninsula of Tiahuanuco and neighbouring islands; the large promontory 

 of Capocabana connected with the west coast by a narrow stem; the long island 

 of Titicaca ; a limestone and sandstone hill which has given its name to the lake ; 

 lastly, the island of Coati and other smaller lands which have become famous 

 in Peruvian mythology. One of these islands is indicated in the national legends 

 as the cradle of man and civilisation. 



Although standing at a high altitude in the cold regions, Titicaca is fringed 

 with an impenetrable foi'est of reeds covering all the low-lying tracts ; it also 

 supports a few animal organisms, amongst others fish of the orcistias family, a few 

 siluridœ (catfish), and eight species of allorchestes, a crustacean apparently of 

 pelasgic origin. f Films of ice are formed around the margin, but Titicaca is 

 never completely frozen, even in the hardest winters. It affords pasturage to 

 animals at all seasons, in summer along the shores, in winter in the water itself, 

 where the}^ graze on a lacustrine vegetation growing down to a depth of 3 or 4 

 feet below the surface. 



Amongst the numerous streams discharging into the lake is the Ramis, which 

 is formed by various torrents descending from the Carabaya and Vilcanota heights, 

 and which presents the aspect of a veritable river. The emissary at the south- 

 eastern extremity of the lake, known simply as the Demcjuadero or " effluent," also 

 discharges a considerable volume deep enough to be navigated by river steamers. 

 This emissar}', flowing south-eastwards in a line with the axis of the plateau, is 

 joined by the Pio de Maure, a large tributary descending from the Western 

 Cordillera and ramifying at the confluence into several mouths. 



The Desaguadero itself divides into a number of branches, which are obstructed 

 by aquatic growths forming extensive thickets frequented by the Uros. These 

 Indian fishers construct floating villages by means of reed rafts, above which are 

 raised matted huts of these plants. In a course of about 200 miles the Desaguadero 

 descends by a uniform incline a total height of 475 feet down to another lacustrine 



* Comparative areas of Titicaca and other large lakes : — 



Square Miles. 



Superior 33,200 



Nyanza 30,000? 



Michigan 24,700 



Tanganyika 15,600 



Baikal 14,000 



Titiciica 3,300 



Geneva 230 



t Alexander Agassiz, Ausland, 1870, part xxxv. 



