ON ITS EXTERIOR. VOLCANOES. 277 



los Eobles ( 402 ) near Popayan, the coast-line and the 

 Cordilleras agree in a course which is even from S. W. to 

 N.E. It seems difficult to determine anything as to the 

 geological causal connection in this frequently manifested 

 accordance between the outlines of continents and the 

 direction of adjacent mountain-chains (South America, 

 Alleghanys, Norway, Apennines). 



Although at present in the volcanic series of Bolivia 

 and Chili, it is the ivestern branch of the Andes, or that 

 nearest to the Pacific, which shows most traces of still-sub- 

 sisting volcanic activity, yet a very experienced observer, 

 Pentland, has also discovered at the foot of the eastern 

 chain, more than 180 geographical miles from the sea, 

 a perfectly preserved but extinct crater with unmistak- 

 able streams of lava. This crater is at the summit of a 

 conical mountain near San Pedro de Cacha, in the valley 

 of Yucay 12,000 feet high (lat. 14 8', long. 71 20'); 

 south-east of Cuzco, where the eastern snowy range of 

 Apolobamba, Caxabaya, and Vilcanoto stretches from 

 S.E. to N.W This noteworthy point ( 403 ) is marked by 

 the ruins of a celebrated temple of the Inca Viracocha. 

 The distance of this former lava-yielding volcano from 

 the sea is much greater than that of Sangay (which 

 also belongs to an eastern Cordillera), and greater than 

 that of Orizaba, or of Jorullo. 



An interval of 540 miles without volcanoes divides the 

 volcanic series of Peru and Bolivia from that of Chili ; 

 this is the distance of the eruption in the desert of 

 Atacama from the volcano of Coquimbo. As already 

 remarked, 2 34' farther to the south the Chilian group 

 of volcanoes reaches its maximum of elevation in 

 Aconcagua, 23,003 feet high, which is also, according to 



