CHAIN OF VOLCANOES. . 325 



volcanoes of the Virgins.* If it were certain that the 

 mountains of California belong to the western branch of the 

 Andes of Analmac, it might be said that the volcanic fire, 

 still burning, abandons the central Cordillera when it re- 

 cedes from the coast, that is, from the volcano of Colima ; 

 and that the fire is borne on the north-west by the penin- 

 sula of Old California, Mount Saint Elias, and the peninsula 

 of Alaska, towards the Aleutian Islands and Kamschatka. 



I shall terminate this sketch of the structure of the 

 Andes by recapitulating the principal features that charac- 

 terize the Cordilleras, north-west of Darien. 



Lat. 8-ll. Mountains of the isthmus of Panama, Vera- 

 gua, and Costa Rica, slightly linked to the western chain of 

 New Grenada, which is that of Choco. 



Lat. 11-1G. Mountains of Nicaragua and Guatimala; 

 line of volcanoes N. 50 W., for the most part still burning, 

 from the gulf of Nicoya to the volcano of Soconusco. 



Lat. 10 18. Mountains of gneiss-granite in the province 

 of Oaxaca. 



Lat. 18i -19| . Trachytic knot of Anahuac, parallel with 

 the Nevados and the burning volcanoes of Mexico. 



Lat. 19^-20. Knot of the metaliferous mountains of 

 Guanaxuato and Zacatecas. 



Lat. 2 If -22'. Division of the Andes of Anahuac into 

 three chains : 



Eastern chain (that of Potosi and Texas), continued by 

 the Ozark and Winconsin mountains, as far as Lake 

 Superior. 



Central chain (of Durango, New Mexico, and the Eocky 

 Mountains), sending on the north of the source of the 

 river Platte (lat. 42), a branch (the Black Hills) to 

 N.E., widening greatly between the parallels 46 and 

 50, and lowering progressively as it approaches the 

 mouth of Mackenzie River (lat. 68). 

 Western chain (of Cinaloa and Sonora). Linked by spurs 



to the maritime Alps, or mountains of California. 

 We have yet no means of judging with precision the 

 elevation of the Andes south of the knot of the mountains 



* Volcanes de las Virgenes. The highest summit of Old California, 

 the Cerro de la Giganta (700 toises), appears to be also an extinguished 

 volcano. 



