364 Revieivs — Agassiz's Coral Reefs of the Pacific. 



" It has tlms been my good fortune to observe the structure of the 

 great majority of the coral reefs, atolls, and coral islands of the 

 tropical Pacific, and to have the benefit of the excellent charts 

 published since the days of Darwin and Dana. 



" One cannot over-estimate the great advantages to be derived 

 from recent surveys in studying groups of coral islands like the 

 Fiji or the Society Islands. The charts and ' Sailing Directions ' 

 contain an amount of information which no one individual could 

 hope to bring together, and their publication has made it possible 

 for an observer to cover an immense area and obtain within 

 a reasonable time an insight into the structure of the coral reefs 

 of an oceanic realm like the Pacific." 



Professor Alexander Agassiz's observations and investigations on 

 coral reefs date back to 1877 (over a quarter of a century), and 

 have now covered the principal coral reefs and islands of the Pacific, 

 the West Indies, and the Indian Ocean. 



"The explorations" (says Agassiz) "were not continued for the 

 sake of proving Darwin to be wrong, as seems to be the impi'ession 

 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 Eeefs.' " 



The author gives a summary of the various and very numerous 

 souices of information on coral reefs which he has been able to 

 consult, including the many missionaries whose journals contain 

 much information regarding coral reefs and islands in which they 

 had spent years ; also to the reports of voyages of English, 

 French, and Russian navigators; he specially cites the voyage of 

 the "Blossom" under Beechy, of the "Beagle" and the United States 

 Exploring Expedition under Wilkes, as memorable for their reports 

 on coral reefs by Darwin and by Dana, and on the geology of the 

 islands of the Pacific. Agassiz also quotes the British Admiralty 

 Surveys, and those of the Frencli Hydrographic Btu'eau, as well as 

 various minor expeditions of the United States Government. 



Sir John Murray's Memoir on the " Structure and Origin of Coral 

 Eeefs" (Proc. R. S. Edinburgh, 1880) is referred to, in which 

 Darwin's theory of the formation of barrier-reefs and atolls was 

 discussed. 



Semper's investigations in the Pelew Archipelago were carried 

 on as far back as 1861, when he spent nearly ten months in the 

 Pelews, and called attention (Leipzig, 1880) to the fact that all 

 kinds of reefs (atolls, barriei", and fringing reefs) are found in the 

 Pelews, within a comparatively short distance, in a region considered 

 by Darwin as one of subsidence, and that at the southern extremity 

 of the group an elevated coralliferous limestone island (Ngaur) rose 

 to a height of over 300 feet, containing, according to Wichman, 

 fossils of late Tertiary age. Semper lays great stress on the effects 

 of currents between the land-rim and the barrier-reef in widening 

 barrier - reef lagoons; and Agassiz has described reef - platform 

 lagoons which illustrate this vpell. 



