GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 325 



Bearing op these Conclusions on Hypotheses of the Formation of Coral 



Reefs. 



How do my results compare with the theories and hypotheses 

 advanced by others? Before considering my conclusions in their 

 relation to those reached by other investigators, I wish to make a few 

 general remarks on the literature appertaining to coral reefs. It is a 

 subject that, in order to be properly treated, requires a considerable 

 diversity of knowledge, as biologic, oceanographic, and geologic 

 problems are involved. Very rarel}^ has it been practicable for a man 

 to be a specialist in all of these fields. Usually, as any investigator 

 has been specially qualified in only one or two of them, he has paid 

 particular attention to those subjects with which he was familiar, and 

 nearly always did good work in those subjects; but in those fields in 

 which he has been only casually engaged, his work is nearlj^ always 

 amateurish, and his conclusions are in many instances erroneous. 

 Should we expect a man who is primarily a biologist to be an expert 

 in geology, especially when he attempts geologic work after he arrives 

 at the place where he expects to conduct his investigations, without 

 having had previous experience ? Should we expect a man who has 

 riveted his attention on dry-land physiography, and who has not 

 thought of biologic problems or of the physiography of the sea 

 bottom to take information from those branches of science? In 

 reading the many pubhcations on coral reefs, I am impressed with the 

 particular, personal interests of the investigators, but what strikes 

 me more forcibly is the excellence of nearly all the papers. I know 

 no paper by a serious scientific man on a coral-reef area that does not 

 contain records of valuable observations and correct conclusions. I 

 have had the wish to write an accoimt of the very gradual growth of 

 the knowledge we now have of coral reefs, and point out how each of 

 the successive workers has contributed toward making that knowl- 

 edge what it now is. It w^ould be a record of honorable achievement. 

 In the short review to follow I trust I may point out some of the 

 substantial additions to be credited to those whose opinions I shaU 

 discuss. 



1. The Darwin-Dana hypothesis, in my opinion, is correct as regards 

 the formation of offshore reefs during and after submergence; but as 

 regards the formation of a prism of reef material, the upper surface 

 of which forms a flat behind the barrier, their theory is wTong for 

 every area on which we have definite information. Although the 

 theoretic possibility of the conversion of a fringing reef into a barrier 

 and a barrier into an atoll may not be denied, no instance of such 

 conversion has yet been discovered. The inferences of Darwin as to 

 areas of subsidence and of elevation, as shown on plate 3 of his work, 

 are largely in error, for barrier ]-eefs are present where there is not 

 general crustal subsidence, as Foye points out in his paper on the 



