RECAPITULATION. 



Extensive observation on the condition of the crust of the earth 

 proves that such forms were not assumed definitely and per- 

 manently at once, but that they underwent a long succession of 

 changes, in the course of which the outlines of land and water 

 were frequently varied : what was land at one time became the 

 bottom of the ocean at another, and what was the bottom of the 

 ocean at one time, rising to the surface, assumed the forms of 

 continents and islands at another. 



It would be easy to show, by an^analysis of the effects produced 

 by such a succession of catastrophes, that they all tended to one 

 definite end ; namely, the final adaptation of the earth for the 

 dwelling-place of the human race, and its contemporaneous tribes. 



After the superficial temperature had fallen sufficiently low to 

 allow of the deposition of water upon the surface, and the forma- 

 tion of an universal ocean, a series of convulsions commenced, 

 each of which was produced by the agency of the matter in 

 igneous fusion contained within the solid shell of the earth. This 

 matter acting unequally against the inner surface of the shell 

 cracked it from time to time, producing fissures, through which 

 the igneous pasty matter issued, 'cooling and solidifying when 

 exposed to the external atmosphere. Each convulsion necessarily 

 changed the relative levels of different parts of the solid surface, 

 and this was attended with a corresponding change in the dis- 

 tribution of the waters of the ocean. Upon the occurrence of 

 each phenomenon, these waters would rush with furious impetuosity 

 over such parts of the land as would fall to a lower level, while 

 at other places the solid bottom of the ocean would rise above the 

 surface of the waters, forming new continents and islands. Such 

 catastrophes must not be regarded as either conjectural or 

 imaginary. They have, on the contrary, left on the earth visible 

 traces by which their occurrence has not only been demon- 

 strated, but even their dates have been geologically ascertained, 

 so that we are enabled to state the order in which they occurred. 



189. For a long period of time, during which these cata- 

 strophes were developed at intervals, the superficial temperature 

 depended infinitely more upon the internal heat transmitted 

 to the surface through the crust, than upon the effects of 

 solar radiation. It must be remembered, that, so far as the 

 superficial temperature would depend upon the heat received 

 from the interior through the crust, the temperature would 

 be everywhere the same. Thus it would affect the poles and 

 the equator equally, and would be equally diffused over all 

 latitudes ; but, on the contrary, so far as the temperature would 

 depend on solar radiation, it would vary with the latitude, as it 

 does at present, being greatest between the tropics, and least 



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