CHAPTER XX 



THE THEORIES OF ATOLL AND REEF FORMATION 

 PUT FORWARD SINCE 1880 



In the space of" more than twenty years that has elapsed 

 since the first publication of the theory of " solution," several 

 other views upon coral formations have been put forward ; 

 but although many observers have dissented from the " solu- 

 tion " theory, no new concrete idea has been formulated to 

 account for all the phases of coral formations. In the dis- 

 cussions which have taken place upon the subject it has been, 

 as a rule, a question of accepting the " solution " theory in 

 the place of the older views of " subsidence " ; and yet there 

 are many observers who appreciate the fact that " subsidence " 

 will not explain all coral structures — and who yet do not 

 accept " solution " as an explanation for the typical form of 

 atolls. 



Professors A. Agassiz and Semper were early opponents of 

 the idea of a subsiding basis ; but, in 1903, Agassiz said {Nature, 

 1903, p. 547) that in his work "no attempt was made to establish 

 any independent general theory." It would appear that the 

 general tendency was to revert to the ideas of Chamisso — views 

 that were put forward in " Kotzebue's First Voyage," long before 

 Darwin formulated his famous theory. Chamisso supposed 

 that the surf was the home, by election, of the reef-building 

 corals, and so those colonies upon the outer edge of the reef 

 grew faster than those within — and in this way a circular 

 reef was formed. What was lacking in Chamisso's theory 

 was a base upon which to build this reef The failure was 

 entirely due to the scant knowledge of the ocean bottom at the 

 time when the theory was put forward : when Darwin over- 

 came the difficulty he adopted the views of Chamisso to a 



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