60 THE EARTH. 



present one of those wonderful objects which carry one's 

 thoughts backwards to the early ages of the world, probably 

 many millions of years, and yet it is found by the peculiar 

 structure of the eyes of these Trilobites that they were 



FIG. 12. EYE OP TKILOBITE. 



placed at the bottom of the sea with perfect power to look 

 upwards at the light of the sun through the transparent 

 waters. The same hand and the same power had then 

 Divine care and solicitude for the well-being of His crea- 

 tures, as great as He has for those of later ages, and these 

 first-formed beings exactly correspond with the account of 

 the creation of animals given in the book of Grenesis, " And 

 God said, let the waters bring forth abundantly the moving 

 creature that hath life." 



At the end of the " transition period " after ages of long- 

 continued disintegration of the rough surface of the earth, 

 and its deposition in strata after thousands of generations 

 of crustaceans, molluscs, and zoophytes had lived and died, 

 depositing their shells at the bottom of the seas, so as to 

 form strata of the carbonate of lime a great and terrific 

 convulsion of nature put a stop to all this quiet and 

 systematic order of things ; for through these long reaches 

 of time, the physical laws of nature had continued to exert 

 their influence, the bulk of the world had gone on radiating 

 its heat into space, and, as a necessary result, had gradually 

 contracted in size. Now, this radiation had doubtless been 

 much retarded by the badly-conducting surface of solid 

 matter which had everywhere covered it, but, although 

 retarded, it could not be prevented, and although the crust 



