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CHAPTER VI. 



THE HARMONIES BETWEEN THE PHYSICAL CONSTITUTION OF THE 

 EARTH AND ITS INHABITANTS. 



The Terrestrial Eevolutions The Formation of Alluvial Plains Beneficial Effects 

 of the Inequalities of the Earth's Surface What do Petrifactions teach? Coal- 

 strata The Subterranean Treasuries of Man Influence of the Change of 

 Seasons on Organic Life. 



THE sun, the planets, or even our satellite the moon, are so 

 far removed from our sphere that we can never hope to ac- 

 quire an accurate knowledge of their structure ; but the earth, 

 our parent and our inheritance, lies open to our view. We traverse 

 it in all its zones, we measure the depth of its waters, we probe 

 its superficial strata, we examine the petrified remains of extinct 

 plants and animals which it harbours in its bosom as in a vast 

 sarcophagus of the past ; we study its annals in the deposits of 

 the primeval ocean, in the effects of its subterranean fires, in 

 its volcanic eruptions, in the heavings and subsidences of its 

 surface ; and thus many of the secrets of its history have been 

 revealed to us, and the eye of science is able to penetrate far 

 back into the times that have preceded the present configura- 

 tion of its continents and seas. 



Thus we know that since immemorial ages water and fire, 

 these two hostile elements, have been constantly engaged in 

 modelling and remodelling its surface; each striving for the 

 mastery, each eager to destroy the formations of its opponent. 



The subterranean fires have never ceased to react against the 

 solid earth -rind which confines them in iron bondage, to pile up 

 mountain- chains above the fissures caused by their expanding 

 force, to heave up continents from the bottom of the seas, to 

 pour forth torrents of liquid stone from the bosom of the 

 volcano, or to shake whole continents, like a lion impatiently 



