1851.) OF THE ROYAL INSTITUTION. 35 
*‘rocks. Such a doubling or crumpling up of these strata, you may 
“then perchance agree with me in thinking, was in a great measure 
“the result of Jateral pressure between two great masses; the crys- 
‘talline centre of the chain upon the South, and the newly upraised 
“deposits on the North, of which the Rigi is a small part only, which 
“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 ! 
“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 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 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 conceive, coincident with that striking phenomenon in the 
«* Alps on which I have tried to rivet your attention, when the first 
“ glacial and icy period affected so large a portion of this hemisphere, 
“and when large portions of our northern lands formed the bot- 
*‘toms of an Arctic sea. But such tracts were bidden to rise again 
‘‘from beneath the waters and constitute the present continents 
‘‘and islands before man was placed on the surface. Our race, in 
“short, was not created until the greater revolutions of which 
«7 have treated had passed away. 
«These grand dislocations belong, therefore, distinctly to former 
“epochs of nature, and their magnitude és enormous when compared 
“with any thing which passes under our eyes, or has been recorded 
