110 



SUPPOSED FOKMEK INTENSITY 



[Ch. VI. 



chapter, is at or near its maximum 



solar tide will amount to two-and-a-half, instead of two feet 

 but the increased power thus derived from solar attractio ' 

 may be neglected by a geologist, seeing that the . configuratio ' 

 of the land now produces differences in the height of the 

 tides to the extent of fifty feet and upwards, instead of those 

 few additional inches gained by proximity to the sun in the 

 case above proposed. During the glacial period, which will 

 be treated of in the ninth and following chapters, the quantity 

 of ice was so great, as to enable it to exert a carrying power 

 far beyond what it exerts at present, or in the ordinary and 



' state of the globe. But such a development of the 

 energy of ice recurring at distant intervals, and for limited 

 periods, is not catastrophic, and is wholly unconnected with 



normal 



mi 



must 



of the planet. In regard also to ice, we 



its action on land is substituted for that of running water. 



mes a mi 



t 



ics, and in scoring, abrading, and polishing rocks ; but mean- 



while the other is in abeyance. When 



example, the 



moraines 



to the lower end of the Lake of Geneva, there was no great 



miles 



and several hundred feet in depth, at the upper end of the lake. 

 ^ Deluges.— As deluges have been often alluded to (page 13, 



$ of the causes which may be 



somethin 



movements 



Geologists who believe that mountain 



m 



convulsions 



and then break in terrific waves upon the land, sweeping over 

 whole continents, hollowing out valleys, and transporting 

 sand, gravel, and erratics to great distances. The sudden 

 rise of the Alps or Andes, it 



is said, may have produced a 

 flood even subsequently to the time when the earth became 

 the residence of man. But it seems strange that none of the 

 writers who have indulged their imaginations in conjectures 

 of this kind, should have ascribed a delude to the sudden 



unfathomable 









