330 CHARLES DARWIN 



(as in the case of the glaciers) we suppose them to have 

 taken place at corresponding distances in Europe : then 

 would the land from the North Sea to the Mediterranean 

 have been violently shaken, and at the same instant of time a 

 large tract of the eastern coast of England would have been 

 permanently elevated, together with some outlying islands, a 

 train of volcanos on the coast of Holland would have burst 

 forth in action, and an eruption taken place at the bottom of 

 the sea, near the northern extremity of Ireland and lastly, 

 the ancient vents of Auvergne, Cantal, and Mont d'Or would 

 each have sent up to the sky a dark column of smoke, and 

 have long remained in fierce action. Two years and three- 

 quarters afterwards, France, from its centre to the English 

 Channel, would have been again desolated by an earthquake, 

 and an island permanently upraised in the Mediterranean. 



The space, from under which volcanic matter on the 20th 

 was actually erupted, is 720 miles in one line, and 400 miles 

 in another line at right angles to the first : hence, in all prob- 

 ability, a subterranean lake of lava is here stretched out, of 

 nearly double the area of the Black Sea. From the intimate 

 and complicated manner in- which the elevatory and eruptive 

 forces were shown to be connected during this train of phe- 

 nomena, we may confidently come to the conclusion, that the 

 forces which slowly and by little starts uplift continents, and 

 those which at successive periods pour forth volcanic matter 

 from open orifices, are identical. From many reasons, I 

 believe that the frequent quakings of the earth on this line 

 of coast are caused by the rending of the strata, necessarily 

 consequent on the tension of the land when upraised, and 

 their injection by fluidified rock. This rending and injection 

 would, if repeated often enough (and we know that earth- 

 quakes repeatedly affect the same areas in the same manner), 

 form a chain of hills; and the linear island of S. Mary, 

 which was upraised thrice the height of the neighbouring 

 country, seems to be undergoing this process. I believe that 

 the solid axis of a mountain, differs in its manner of forma- 

 tion from a volcanic hill, only in the molten stone having 

 been repeatedly injected, instead of having been repeatedly 

 ejected. Moreover, I believe that it is impossible to explain 

 the structure of great mountain-chains, such as that of the 



