T. W. Vaughan — Origin of Barrier Coral Reef s. 131 



Art. Y. — The Present Status of the Investigation of the 

 Origin of Barrier Coral Reefs ; by Thomas Watlamd 

 Yaughan."" 



[A preface to "Relations of Coral Eeefs to Crust Movement in the Fiji 

 Islands," by E. C. Andrews.] 



As the paper by Mr. Andrews, which follows this, has an 

 important bearing on the theory of the formation of coral 

 reefs, it seems appropriate that it should be preceded by a 

 sketch of the principal hypotheses advanced to account for 

 such structures and a brief resume of the results of some of 

 the more recent studies. 



The history of coral reef theory is usually dated from the 

 appearance of Darwin's " Structure and distribution of coral 

 reefs" in 1812, although he had previously announced his 

 views in 1837, and important and astute observations on corals 

 and coral reefs had been published by Chamisso as early as 

 1821. As the views of Dana, based upon his observations 

 made while on the Wilkes Exploring Expedition and published 

 in 1819, accorded with those of Darwin, the hypothesis 

 advanced by the latter and supported by the former is generally 

 known as the Darwin-Dana hypothesis. According to it bar- 

 rier reefs and atolls are to be explained by corals first forming 

 a fringing reef on the sloping shore of a subsiding land area ; 

 the reef grows upward at such a rate that its top remains near 

 the surface of the water and through the retreat of the shore 

 it is converted into a barrier ; continued subsidence where the 

 inclosed land -area is an island may result in the production of 

 an atoll circumscribing a lagoon without any land mass pro- 

 jecting above the water level. It should be emphasized that 

 this hypothesis involves more than mere subsidence and the 

 conversion of a fringing into a barrier reef. It also attempts 

 to account for extensive submarine platforms by assuming that 

 they have been built upon sloping basements behind barrier 

 reefs through agencies dependent on the presence of corals. 



The first important protest against this hypothesis was made 

 by Carl Semper, who, in 1863, after studies in the Pelew 

 Islands, published the opinion that atolls could be formed in 

 areas of elevation by the solution of the interior of pre- 

 existent masses of limestone, and that solution, erosion by cur- 

 rents, and wave-cutting might develop platforms behind 

 fringing reefs. Subsequent to Semper, the students of the 

 coral reef problem arrayed themselves in two camps, one of 

 which supported while the other opposed the interpretations 

 of Darwin and Dana, Among the most important opponents 



* Published by permission of the Director of the United States Geological 

 Survey. 



