jS. H. Howorth — Elevation of American Cordillera. 441 



II. — The Eecent and Eapid Elevation of the American 

 Cordillera. 



By Henky H. Howorth, Esq., M.P., etc., etc. 



IN some papers which have lately appeared in the Geological 

 Magazine, I have endeavoured to show that the Ural 

 Mountains, and also the great masses of high land in Eastern 

 Asia from the Altai to the Himalayas, are of very recent geological 

 origin, and that it was probably their rapid elevation which caused 

 the great diluvial movement of which traces are to be found all over 

 the Siberian plains. I now wish to call attention to some of the 

 evidence which points to the American Cordillera being also a very 

 recent geological feature, and dating from the same period of cata- 

 clysmic revolution which closed the Mammoth age. 



It is a curious fact that one name, America, connotes both of the 

 great continents hung together by the isthmus of Panama. The 

 cause of this is of course purely historical, and yet it coincides with 

 a great physical fact, namely, their essential unity in more than one 

 respect. The generic unity of the old inhabitants of both continents 

 is a peculiar fact in ethnography ; but the unity is even more remark- 

 able in this, that the vertebral column which runs north and south 

 through the two Americas is essentially one backbone. 



On this subject Humboldt writes with his usual lucidity and 

 force. Speaking of the great chain of mountains that runs through 

 both continents, he says : " This is the most continued, the longest, 

 the most constant in its direction from south to north, and north- 

 north-west, of any chain of the globe. It approaches the north and 

 south poles at unequal distances of from 22° to 33°. Its develop- 

 ment is from 2800 to 3000 leagues (20 to a degree), a length equal 

 to the distance from Cape Finisterre in Galicia to the North-East 

 Cape (Chukchoi-Noss) of Asia. Somewhat less than the half of 

 this chain belongs to South America, and runs along its western 

 coast. On the north of the isthmus of Capica and of Panama, after 

 an immense lowering, it assumes the appearance of a nearly central 

 ridge, forming a rocky dyke that joins the great continent of North 

 America to that of the South. ... As the continent beyond the 

 parallel of Florida again widens towards the east, the Cordilleras, 

 of Durango and New Mexico as well as the Rocky Mountains, which 

 are a continuation of those Cordilleras, appear to be thrown anew 

 towards the West, that is, towards the coast of the Pacific Ocean ; 

 but they still remain eight or ten times more remote from it than in 

 the southern hemisphere. We may consider as the two extremities 

 of the Andes, the rock or granitic isle of Diego Ramirez, south of 

 Cape Horn, and the mountains that reach the mouth of the Mackenzie 

 River (lat. 69°, long. 130^°), more than twelve degrees west of the 

 Green Stone Mountains, and known by the denomination of the 

 Copper Mountains" (Humboldt's Narrative, vol. vi. pp. 409-411). 



It is to this chain chiefly that I wish to direct your readers. 



The first and most remarkable fact to which I would draw atten- 

 tion is that throughout its vast length (in places towering to an 



