Mr. Pentland's Observations on the Peruvian Andes, 117 



of the Andean chain. The Nevados of Utimani and of Sorata 

 (those referred to in Mons. de Montbret's paper) surpassing in 

 height the giants of the Columbian prolongation of the Andes, 

 Chimborazo, Cayambe and Antisana, — and approaching near 

 to the most elevated peaks of the Himalaya range. 



" The mountain of Illimani is situated in the Bolivian pro- 

 vince of La Paz, twenty leagues E.S.E. of the city of the same 

 name. Like Chimborazo it forms the most southern limit of 

 the snowy range to which it belongs ; and according to my 

 astronomical observations, (made at La Paz, and at the hamlet 

 of Jotoral near to its northern base,) it is placed between 

 16° 35' and 16° 40' south latitude ; and between the 67th and 

 68th degrees of west longitude, reckoned from the meridian of 

 Greenwich. Its summit forms an elevated ridge, surmounted 

 by four peaks, disposed on a line from north to south and 

 parallel to the axis of the chain. The most northern of these 

 eminences attains an elevation, according to my measurement, 

 of 24,200 British feet, or 12,000 feet above the city of La Paz ; 

 but the southernmost peak appeared to me to be still more 

 elevated, although it was impossible to ascertain the exact dif- 

 ference from my station. This stupendous mountain is com- 

 posed of grauwacke and transition-slate, with frequent inter- 

 stratifications of quartz-rock and flinty-slate; which in their 

 mineralogical structure and geological relations entirely re- 

 semble those of the valleys of the Maurienne and Tarentaise in 

 the Savoy Alps : and with these schistose rocks are associated 

 large masses of porphyry, of sienite, and of true granite, in 

 the form of veins and beds. The transition -slate is traversed 

 by numerous veins of quartz, containing minute portions of 

 gold and of auriferous pyrites; many of which veins were 

 worked by the aboriginal Peruvians, at an elevation of 1 6,000 

 feet above the level of the sea, at a very remote period, prior 

 to the arrival of their Europaean invaders. 



" The most eastern point of the coast of the Pacific, on the 

 same parallel of latitude with the mountain of Illimani, is si- 

 tuated between the roads of Quilca (latitude 16° 42'), and the 

 headland or Morio of Arequipa (latitude 16° 30' S.) ; and 

 between the meridians of 72° 40', and 73° 20' W. of Green- 

 wich, — adopting a mean of the observations of Captain Basil 

 Hall, and of Alessandro Malespina. Illimani is consequently 

 separated from the nearest point of the coast of Peru, by an 

 horizontal distance equal to 5° 30' of longitude, or to 310 

 nautical miles. This fact in itself is sufficient to show the im- 

 possibility of discovering from the coast of Peru, that moun- 

 tain, or indeed any part of the eastern cordillera of the Andes 

 (the axis of which, between the 14th and 17th degrees of lati- 

 tude, 



