xii INTRODUCTION. 



was extended the subject proved far more complicated than had been sus- 

 pected by previous investigators. The explorations were not continued for 

 the sake of proving Darwin to be wrong, as seems to be the impression of 

 some of my critics. Year after year the subject of coral reefs became more 

 engrossing, and it was studied for its own sake. I had no theory of my 

 own as a guiding star, nor did I attempt to uphold any one of the theories 

 on coral reefs advanced since the publication of Darwin's " Structure and 

 Distribution of Coral Reefs." 



An immense amount of information regarding the coral reefs and islands 

 of the Pacific may be found in the journals of missionaries, who have often 

 spent years at certain localities. Some of the descriptions by Williams, 

 Whitmee, Gill, and Turner are remarkably accurate, and many of their illus- 

 trations most interesting ; especially instructive are the reports of the 

 voyages of English, French, and Russian navigators in the last part of the 

 eighteenth and beginning of the nineteenth century, containing the first 

 accurate charts of atolls, barrier and fringing reefs published. 



A number of independent travellers have also published sketches of their 

 journeys. The voyage of the " Blossom " under Beechey,^ of the " Beagle," 

 and the United States Exploring Expedition under Wilkes, are memorable 

 for Darwin's and Dana's reports on coral reefs and the geology of the 

 islands of the Pacific. 



These expeditions have been supplemented by the surveys of the British 

 Admiralty and the French Hydrographic Bureau, as well as by several 

 minor expeditions sent out by the United States Government. Their 

 results include the publication of a series of excellent charts covering nearly 

 all the oceanic island groups of the tropical Pacific, like those of Fiji, of 

 Tonga, of the Society Islands, and of many of the Line Islands ; they far 

 surpass in accuracy the earlier publications and give us a very different 

 idea of the structure of atolls, of coral reefs, both fringing and barrier, 

 from that obtained from data available fifty years ago. 



Since the " Challenger " expedition, dating with the appearance of Mur- 

 ray's " Structure and Origin of Coral Reefs " in 1880/ Darwin's theory of 



1 An excellent analysis of the results of Beechey's voyages by Ainsworth will be found in the 

 Journal of the Royal Geographical Society of London, Vol. I., 1831, p. 193. 



2 Proceedings of the Royal Society of Edinburgh, X., p. 508. 



