18 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



justified in denying that the Paumotus as such are situated in an area of 

 subsidence, and that subsidence has been the great factor, as is maintained 

 by Darwin and Dana, in the formation of the characteristic atolls of the 

 group. 



It may be well to point out also that the Paumotus, like the Marquesas 

 on one side and the Society Islands on the other, are situated upon a 

 plateau siuiilar to that upon which the last-mentioned groups are placed, 

 a plateau rising from an oceanic basin which surrounds them, and which 

 has a depth of from 2300 to 2500 fathoms, the plateau itself having a 

 depth of 1200 to 1500 fathoms. For the differences which distinguish the 

 plateaux of these groups I refer to the accompanying charts. 



During our stay in Papeete' some time was spent in examining that 

 part of the barrier reef of Tahiti which had been surveyed by the '* Chal- 

 lenger." We found the condition of the outer slope of the reef quite 

 different from its description as given in the " Challenger " narrative.^ 

 The growing corals were comparatively few in number, and the outer 

 slope showed nothing but a mass of dead corals and dead coral bowlders 

 beyond sixteen or seventeen fathoms, few living corals being observed 

 beyond ten to twelve fathoms. 



We also made an expedition to Point Venus, to determine, if possible, 

 the rate of growth of the corals on Dolphin Bank from the marks which 

 had been placed on Point Venus by Wilkes, in 1839,^ and by MM. Le Clerc 

 and de Benaze, of the French navy, in 1869. We found the stones and 

 marks as de.scribed, but in view of the nature and condition of Dolphin 

 Bank, did not think it worth while to make a careful survey, as Captain 

 Moser had intended to do. On examining Dolphin Bank in the steam 

 launch I was greatly surprised to find that there were but few corals 

 growing on it. I could see nothing but sparsely scattered heads, none 



1 Explorations of the "Albatross" in the Pacific. II. The Paumotus. [Letter No. 2, dated 

 Papeete Harbor, Tahiti Island, November 6, 1899, to Hon. George M. Bowers, U. S. Commissioner 

 of Fish and Fisheries, Washington, D. C, by Alexander Agassiz.] Am. Jour. Sci., Fourth Series, 

 Vol. IX., No. ,50, February, 1900. 



^ Voyage of the "Challenger," Narrative of the Cruise, 2d Part of Vol. I., p. 778. 



' U. S. Exploring Expedition Narrative, Vol. II. 



