1898.] Funafuti, Rotwna and Fiji. 503 



the plateau 50 — 250 fathoms in depth, which bears his name. Of 

 this plateau L. Agassiz says 1 that it "is built up entirely by 

 animals now living upon its surface and constantly increasing 

 the thickness of the bed by. their accumulation. Large fragments 

 of the rock were brought up by the dredge ; so that its structure 

 and characteristic remains of animals could be studied at leisure. 

 I do not know that there is on record a more direct illustration 

 of the manner in which mountain masses of calcareous deposits 

 have been accumulated on the bottom of the. ocean." This rock 

 it must be observed Agassiz compared to the coral rag in the 

 Jurassic. Agassiz speaks also of the abundant fauna of this 

 plateau, one remark, " the variety of marine plants does not keep 

 pace with the variety of marine animals," being of interest as 

 indicating that some plants at any rate were found all over this 

 plateau. 



I have shown sufficiently by these few quotations, how banks 

 may grow up to the requisite height for the reef-building nulli- 

 pores. In the tropics corals would grow more vigorously and at 

 greater depths on account of the abundance of food and probably 

 the greater intensity of the light than in the temperate zone, 

 where the pelagic life is not so rich. That reefs are not formed 

 in the temperate zones is due, in the first place to solution, in 

 the next to the inability of the reef-building nullipores to live and 

 flourish in these temperatures ; these algae require moreover a 

 strong and direct light, and such light can only be obtained at 

 considerable depths in the tropical regions. 



These few remarks, which I have made, are intended to apply 

 more particularly to the coral reefs of Fiji, as well as generally 

 to those of the Pacific and Indian Oceans. I would not wish to 

 apply them to the Florida Reefs and other reefs in the West 

 Indies, where I think the conditions of formation were radically 

 different; the formation of the Great Barrier Reef of Australia 

 may probably be explained in a similar way to that by which 

 L. Agassiz has explained the Florida Reefs. Each step in the 

 formation of atoll and barrier reefs, as I have tried to sketch 

 it, cannot, I fear, be applicable to all atoll and barrier reefs. 

 Nevertheless the main outlines will, I believe, be found to be 

 correct for most of the so-called coral reefs, but each group of 

 islands and each reef should be considered by itself in relation 

 to the known meteorological and biological conditions of its region. 



1 Report on Deep Sea Dredgings in the Gulf Stream. Mus. Comp. Zool., 1870. 



