On the former chayiges of the Alps. 249 



the north of which the Rigi is a small part only, which latter 



having been intruded upon the terrestrial surface, necessarily com- 

 pressed 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 shghtly 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! 



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

 know it may 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 ex- 

 ternal features of this rind^ they are truly stupendous. How, for 

 example, can the observer travel over vast surfaces such as Rus- 

 sia, 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 se- 



quence of former aqueous deposits, which, simply dried up, have 

 never been disturbed by any violent revolutions from beneath, 

 ^nd then compare them with the adjacent Ural mountains, or 

 still better with the loftier Alps, and not 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 

 lossil mammalia, that such also have been the changes, though 

 ^n a less scale, in our own country. The large extinct British 

 q^jadrupeds necessarily required a great range for their sustenance. 

 1 hey had doubtlessly roamed from distant tracts to our lands be- 

 tofe the straits of Dover were formed and before the British do- 

 i^mions were broken into isles. Our great insular dislocations 

 ^^re, I conceive, coincident with that striking phenomenon in 

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

 pst glacial and icy period affected so large a portion of this hem- 

 isphere, and wlien large portions of our northern lands formed 

 \he bottoms of an Arctic sea. But such tracts were bidden to 

 rise again from beneath the waters and constitute the present 

 J^ntments and islands before man was placed on the surface. 

 Y^ race, in short, was not created until the greater revolutions 

 j^^'^h I have treated had passed away. 

 These grand dislocations belong, therefore, distinctly to for- 

 *^er epochs of nature, and their magnitude is enormous when 

 J^mpared with any thing which passes under our eyes, or has 

 peen recorded in human history. At the same time geologists 

 "^^e shown upon clear evidences, that during the long and coni- 



Secoxd SEarKa, VoL XII, No. 35.-SepL, 1851. 32 



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