1 68 CORAL-REEFS. 



observes, rises above the height of true lagoon-islands), coral- 

 rock, like that on the beach, was found. In the Navigator 

 Archipelago, Mr. Couthouy 1 found on Manua many and very 

 large fragments of coral at the height of eighty feet, " on a 

 steep hill-side, rising half a mile inland from a low sandy plain 

 abounding in marine remains." The fragments were em- 

 bedded in a mixture of decomposed lava and sand. It is not 

 stated whether they were accompanied by shells, or whether 

 the corals resembled recent species ; as these remains were 

 embedded they possibly may belong to a remote epoch ; but I 

 presume this was not the opinion of Mr. Couthouy. Earth- 

 quakes are very frequent in this archipelago. 



Still proceeding westward we come to the New Hebrides; on 

 these islands, Mr. G, Bennett (author of Wanderings in New 

 South Wales) informs me he found much coral at a great 

 altitude, which he considered of recent origin. Respecting 

 Santa Cruz and the Salomon Archipelago, I have no infor- 

 mation ; but at New Ireland, which forms the northern point of 

 the latter chain, both Labillardiere and Lesson have described 

 large beds of an apparently very modern madreporitic rock, 

 with the form of the corals little altered. The latter author 3 

 states that this formation composes a newer line of coast, 

 modelled round an ancient one. There only remains to be 

 described in the Pacific, that curved line of fringed islands, 

 of which the Marianas form the main part. Of these Guam, 

 Rota, Tiniam, Saypan, and some islets farther north, are 

 described by Quoy and Gaimard, 3 and Chamisso, 4 as chiefly 

 composed of madreporitic limestone, which attains a consider- 

 able elevation, and is in several cases worn into successively 

 rising cliffs : the two former naturalists seem to have compared 

 the corals and shells with the existing ones, and state that they 

 are of recent species. Fats, which lies in the prolonged line 



1 Remarks on Coral- Formations \ p. 50. 



2 Voyage de la Coquille, Part. Zoolog. 



3 Freycinet's Voyage atitour du Motide. See also the Hydrographical 

 Metnoir, p. 215. 



4 Kotzebue's First Voyage, 



