226 CORALS AND CORAL ISLANDS. 



Mr. Stevenson states also that the Bell Rock Lighthouse, 

 in the German Ocean, though one hundred and twelve feet in 

 height, is literally buried in foam and spray to the very top, 

 during ground swells, when there is no wind. On the 20th 

 of November, 1827, the spray rose to the height of one hun- 

 dred and seventeen feet above the foundations or low-water 

 mark; and deducting eleven feet for the tide that day, it 

 leaves one hundred and six feet, which is equivalent to a pres- 

 sure of nearly three tons per square foot. 



With such facts, any incredulity respecting the power of 

 waves should be laid aside. Moreover, it may be remarked 

 that the Pacific is a much wider ocean than the Atlantic, with 

 far heavier waves in its ordinary state. 



We must, therefore, allow that some effect will be pro- 

 duced upon the coral groves. There will be trees prostrated 

 by gales, as on land, fragments scattered, and fragmentary 

 and sand accumulations commenced. Besides, masses of the 

 heavier corals will be uptorn, and carried along over the coral 

 plantation, which will destroy and grind down every thing in 

 their way. So many are the accidents of this kind to which 

 zoophytes appear to be exposed, that we might believe they 

 would often be exterminated, were they not singularly tenacious 

 of life, and ready to sprout anew on any rock where they may 

 find quiet long enough to give themselves again a firm attach- 

 ment. 



But it should be observed, that the sea would have far 

 less effect upon the slender forms characterizing many zoo- 

 phytes, among which the water finds free passage, than on the 

 massive rock, against whose sides a large volume may drive 

 unbroken. Moreover, much the greater part of the strength 

 of the ocean is exerted near tide level, where it rises in break- 

 ers which plunge against the shores. Yet owing to the many 



