AGASSIZ: FIJI ISLANDS AND COEAL KEEFS. 29 



denudation and erosion somewhat more advanced than that existmg on 

 the eastern half of the south shore of Kandavu. 



We cannot fail to notice also the greater width of the shore platform 

 wherever the coast has a northerly trend, as, for instance, west of Tomba 

 ni Richmoudi on the north coast, and north of the John Wesley Bluffs, 

 where the platform is edged by the jNIalatta Reefs and studded with 

 heads and patches. On the northern coast, however, the frhiging reefs 

 are narrow, while on the south coast of Kandavu (Plate 10) they take 

 their greatest development, exposed to the full sway of the southeast 

 trades. A glance at Plate 11 cannot fail to show the relatively great 

 width -of the eastern belt of the encircling reef, as compared with that 

 of the western side of the Great Astrolabe Lagoon.^ In a smaller lagoon 

 like Nortli Astrolabe Reef, where the breakers pour over the eastern 

 face, and water flows constantly over the western edge, the difference 

 in the width of the reef on the two sides is not so marked. 



While undoubtedly the widt-li of a reef depends in great measure on 

 the nature of the platform upon which it grows, yet I do not see the 

 force of Lendenfeld's statement,^ that while " lateral growth of corals no 

 doubt takes place, it is not the actual cause of the formation of the 

 great coral reefs." There certainly is nothing to prevent the swarms of 

 embryos which float at certain times in the vicinity of a coral reef from 

 attaching themselves and growing upon any surface witliin reach having 

 the proper deptli on both sides of any growing reef. Undoubtedly the 

 extension within the lagoon, both in barrier reefs and atolls, of the coral 

 heads is due to such a cause, and the wider the reef the closer do the 

 heads come together as we pass upon the I'eef fiat from the inner edge of 

 the reef towards the outer marcrin. lu an account of a discussion on 

 coral reefs ^ by Sollas, Hickson, Rothpletz, and others, Stebbiug stated 

 that young corals might start on either rising or subsidence, but only 

 subsidence is favorable. That, it seems to me, depends entirely on the 

 depth at which they start; they may have 120 feet, and build up a reef 

 of that thickness, which is fully as thick as most reefs we know anything 

 about. 



1 I cannot agree with Gardiner in his statement that the windward reefs of Fiji 

 are of about the same breadth. {Loc. cit., p. 4'.i2.) Compare the windward reefs of 

 Mbengha, of the Great Astrolabe Reefs, and of the east coast of Viti Levuwith the 

 windward reefs of Wakaya, of Nairai, of Totoya, of the Budd Reef, of Kanathea, 

 of the Exploring Isles, of the Argo Reefs, of Lakemba, of Aiwa, of Mothe, and of 

 Ongea ; the latter are certainly as a rule mucli narrower than tlie former. 



2 Nature, Vol. XLII. p. 31. 



3 Nature, October 12, 1893, p. 575. 



