190 Sir William Martin Conway [May 26, 



perceived. At one time, when the waters of the inland sea washed 

 the foot of this side of the mountains, the glaciers probably descended 

 into it ; and, even since the drying up of this ancient sea, the glaciers 

 have descended several miles further down than they now do. The 

 high plateau is bordered to the west by an irregular range of peaks, 

 chiefly of volcanic origin. 



During the course of the expedition the main range was triangu- 

 lated, and a sketch survey was made of the western slopes and of the 

 peaks lying between Sorata and Illimani. The northern half of the 

 Cordillera Eeal — the portion, that is to say, which lies between Mounts 

 Sorata and Cacaaca — consists of a series of lofty snow mountains, 

 many of them of very pointed form, which stand one beside another 

 in close proximity, so that the passes over this part of the range 

 seldom sink below the level of perpetual snow. South of Cacaaca 

 the character of the range is different ; the mountains are less pre- 

 cipitous in form and there are wide openings between them, dropping 

 to levels little above that of the plateau. The mountains them- 

 selves are uninhabited, but the plateau bears a relatively dense 

 population of Aymara Indians, whilst in the two towns of La Paz 

 and Sorata the white population is considerable. La Paz is the 

 commercial capital of Bolivia ; Sorata occupies an important position 

 on the main route leading from the plateau to the rich valleys and 

 india-rubber forests to the eastward. This route is of great antiquity, 

 for in the days of the Incas, and possibly long before them, the gold- 

 bearing character of the river gravels in the valleys descending to 

 the north-east and east from Mount Sorata was known to the natives. 



Besides the collection of rock specimens made throughout the 

 range, which are being examined by Professor Bonney, small collec- 

 tions were likewise made of the high-level plants, insects and birds, 

 which have been sent to Kew and the British Museum respectively. 

 The only animals found at relatively high levels were bizcachas, 

 mountain deer and a few vicunas. The flora of the high levels is 

 very sparse at the time when the mountains are accessible to a 

 traveller, though probably after the rainy season has set in there is 

 a greater floral wealth than was observed by our expedition. 



Bolivia is known to be a country rich in mineral deposits, but few 

 signs of mineral wealth were observed at very high altitudes. It is 

 not in the heart but on the flanks of the range that the chief mineral 

 deposits have been discovered. Gold is found chiefly in the valleys 

 running eastward from Mount Sorata, and in the La Paz valley and 

 its branches. Important deposits of tin are known near Cacaaca; 

 cobalt and antimony are likewise found in the same neighbourhood, 

 but I do not think that any copper has been discovered actually in 

 the Cordillera Eeal. The chief copper mines are those about Coro- 

 coro, whilst along the route from La Paz to Antofagasta there is 

 immense and largely undeveloped mineral wealth of all kinds. 



On leaving Bolivia, a brief visit was paid to the great mountain, 

 Aconcagua, near the Chilian-Argentine frontier, and one of its 



