How Animals Work. 



tions, sufficient to raise the summits of submerged 

 mountains to a level where the reef-forming corals can 

 commence to flourish. But these isolated cases all 

 require far more careful and systematic investigation 

 than they have yet received, and though, under certain 

 favourable conditions, atolls and reefs may thus be 

 formed without the subsidence of land, their presence 

 in no way upsets Darwin's theory as applied to the 

 innumerable examples of the various reef formations 

 which stud the Indian, Atlantic, and Pacific Oceans." 



No matter in what situation the skeletons of these 

 reef-building corals may be found whether at a height 

 of 7,000 feet above the level of the sea, or at a depth 

 of 300 feet beneath its surface they must have grown 

 and formed their beautiful and wondrous skeletons 

 within about twenty fathoms of the siirfade of the 

 sea. On the summit of the lofty mountains of Tahiti, 

 at 5,000 and 7,000 feet above the sea level, a regular 

 stratum of semi-fossilized coral has been found ; while 

 it has also been dredged up from 200 to 300 fathoms, 

 to which depth it must have been dragged down by a 

 gradual subsidence of the foundation upon which the 

 living, reef-building corals once flourished. It is a 

 marvellous story of earth movement, written by Nature 

 upon the face of the earth in characters that all may 

 read, and as we ponder those slow but certain upward 

 and downward movements of the land, Tennyson's 

 lines stand out in their crystal truth : 



" The hills are shadows, and they flow 

 From form to form, and nothing stands ; 

 They melt like mist ; the solid lands, 

 Like clouds they shape themselves and go." 

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