CHAPTER H. 



THE EOZOIG AGES. 



THE dominion of heat has passed away; the excess 

 of water has been precipitated from the atmc sphere, 

 and now covers the earth as a universal ocean. The 

 crust has folded itself into long ridges, the bed of the 

 waters has subsided into its place, and the sea for the 

 first time begins to rave against the shores of the 

 newly elevated land, while the rain, washing the bare 

 surfaces of rocky ridges, carries its contribution of 

 the slowly wasting rocks back into the waters whence 

 they were raised, forming, with the material worn from 

 the crust by the surf, the first oceanic sediments. 

 Do we know any of these earliest aqueous beds, or 

 are they all hidden from view beneath newer deposits, 

 or have they been themselves worn away and de- 

 stroyed by denuding agencies ? Whether we know 

 the earliest formed sediments is, and may always 

 remain, uncertain ; but we do know certain very 

 ancient rocks which may be at least their immediate 

 successors. 



Deepest and oldest of all the rocks we are ac- 

 quainted with in the crust of the earth, are certain 

 beds much altered and metamorphosed, baked by 

 the joint action of heat and heated moisture rocka 



once called Azoic, as containing no traces of life, 



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