PREFACE. xi 



light over the subject, and called forth feelings of peculiar 

 satisfaction, and of gratefulness to Mr. Darwin, which still 

 come up afresh whenever the subject of coral islands is men- 

 tioned. The Gambler Islands, in the Paumotus, which gave 

 him the key to the theory, I had not seen; but on reaching the 

 Feejees, six months later, in 1840, I found there similar facts 

 on a slill grander scale and of more diversified character, so 

 that I was afterward enabled to speak of his theory as estab- 

 lished with more positiveness than he himself, in his philosophic 

 caution, had been ready to adopt. His work on Coral Reefs 

 appeared in 1842, when my Report on the subject was already 

 in manuscript. It showed that the conclusions on other points, 

 which we had independently reached, were for the most part 

 the same. The principal points of difference relate to the 

 reason for the absence of corals from some coasts, and the 

 evidence therefrom as to changes of level, and the distribution 

 of the oceanic regions of elevation and subsidence — ^topics 

 which a wide range of travel over the Pacific brought directly 

 and constantly to my attention. 



In the preparation of the present work my former chapter 

 on Coral Reefs and Islands has been greatly extended by the 

 addition of facts from numerous sources. The authorities cited 

 from are stated in the courseof the volume, and need not here 

 be rementioned. I have occasion, however, for special ac- 

 knowledgments to our excellent Yale Zoologist, Professor A. 

 K. Vp:rrill, who now stands first in the country in the depart- 

 ment of Zoophytes. Through his recent memoirs on the subject, 

 and also by his personal advice, I have been greatly aided in 

 acquainting piyself with the present state of the science : — my 

 own special labours in this branch of Zoology having ended 

 in 1850, when both the Reports referred to above had been 

 published, and the last of my Expedition departments — that 

 of the Crustacea — forced my studies in another direction. 



The illustrations of the following pages have been drawn 

 mainly from my Expedition Reports. Those not my own are 



