N 



64 VULCANISM ITS NATUKE AND FUNCTION. 



some areas, and in others seems gradually declining ; but 

 at the same time we behold it breaking forth in new areas, 

 and on a survey of the whole world, see no reason to con- 

 clude that it is now either less extensive in its distribution 

 or diminishing in its intensity. The Andes, through whose 

 extreme length the earthquake and volcano are ceaselessly 

 active, are as gigantic as the Himalaya, where they have 

 long since ceased to exist ; the Mexican Cordilleras broader 

 and loftier than the Alps ; the Alps more imposing than 

 the older Pyrenees ; and the Pyrenees as decided in their 

 character as the primitive ranges of Scandinavia. The 

 cincture of volcanic action that girdles the Pacific (in the 

 Andes, Californian Sierras, Aleutian Isles, Kamtschatka, 

 Japan, Philippine Islands, the Indian Archipelago, and 

 New Zealand, to say nothing of the groups that stud its 

 bosom) is as gigantic as any axis or area geology has re- 

 vealed,* while the individual discharges and irruptions are 

 unexcelled by those of any former period : and in corrobora- 

 tion of this we need only point to the lava streams of Etna, 

 from twenty to forty miles in length to those of Iceland, full 

 fifty miles in length, by twelve to fifteen in width ; or to 



* In absence of a map the following arrangement may convey to the 

 reader a general idea of the disposition of these volcanic lines and centres. 

 1. Along the borders of the Pacific : Throughout the entire length of 

 the Andes from Tierra del Fuego northwards ; in Central America ; 

 Mexico ; Oregon ; the Aleutian Islands ; Kamtschatkan peninsula ; the 

 Kuriles ; Japan group ; Philippines ; East India Islands ; New Guinea ; 

 East coast of Australia and New Zealand. 2. Over the Pacific : In the 

 Sandwich Islands ; Friendly Islands ; Fejees ; Santa Cruz group ; New 

 Hebrides ; and the Ladrones. 3. Over the seas that lie between the northern 

 and southern continents, and adjacent regions ; West India Islands ; the 

 Mediterranean and its borders ; the southern borders of the Caspian and 

 eastward ; and the East Indian Archipelago as lying between Asia and 

 Australia. 4. In the Indian Ocean ; Bourbon and the Mauritius ; 

 Comoro group ; and Madagascar. 5. In the A tla-ntic : St Helena ; the 

 Cape Verdes ; Canaries ; Madeira ; Azores ; and Iceland. The interiors 

 of the great continental masses both in the old and new worlds are still 

 and quiescent. 



