On the former Changes of the Alps. 87 



latter having been intruded upon the terrestrial surface, 

 necessarily compressed the pre-existing formations into a 

 smaller compass. If more adventurous, you should climb 

 to peaks rising to 8000 or 9000 feet above the sea, that 

 flank the central summits, you may there satisfy yourself, 

 that deposits, which were once mere mud, formed during 

 the same time as our slightly consolidated London clay, 

 have been in many parts converted into schists and slates 

 as crystalline as many of the so-called primary rocks of our 

 islands. So intense has been the metamorphosis 1 



" In speaking of the last changes of the Alps as stupendous, 

 I know it mav be said that, in reference to the diameter of 

 the planet, the highest of these mountains and the deepest 

 of these valleys are scarcely perceptible corrugations of the 

 rind of the earth. But when we compare such asperities 

 with all other external features of this rind, they are truly 

 stupendous. How, for example, can the observer travel 

 over vast surfaces such as Russia, and not be able there to 

 detect a single disruption — not one great fracture, and no 

 outbursts whatever of igneous and volcanic rocks ; but, on 

 the contrary, a monotonous and horizontal sequence of 

 former aqueous deposits, which, simply dried up, have never 

 been disturbed by any violent revolutions from beneath, and 

 then compare them with the adjacent Ural Mountains, or 

 still better with the loftier Alps, and not to be impressed 

 with the grandeur of such changes % 



" And here my auditors will recollect, that even beneath 

 and around this metropolis they can be assured by finding 

 extinct fossil mammalia, that such also have been the 

 changes, though on a less scale, in our own country. The 

 large extinct British quadrupeds necessarily required a great 

 range for their sustenance. They had doubtlessly roamed 

 from distant tracts to our lands before the straits of Dover 

 were formed and before the British dominions were broken 

 into isles. Our great insular dislocations were, I con- 

 ceive, coincident with that striking phenomenon in the 

 Alps on which I have tried to rivet your attention, when the 

 first glacial and icy period afi^ected so large a portion of this 

 hemisphere, and when large portions of our northern lands 

 formed the bottoms of an Arctic sea. But such tracts w^pg 



