136 CORALS AND CORAL LS LANDS. 



Fakaafo, or Bowditch (Fig. 5), 200 miles north of the 

 Navigator Islands, is the type of a large part of coral islands. 

 The bank of reef has only here and there emerg;ed from the 

 waves and become verdant; in other portions the reef is ot 

 the usual height, — that is, near low-tide level, — excepting a 

 few spots elevated a little by the accumulation of sand. 



The Paumotu Archipelago, the crowded cluster of coral 

 islands east and north-east of Tahiti, is a most instructive study 

 for the reader; and a map of these islands by the Wilkes Ex- 

 ploring Expedition, inserted in the Narrative of the Expedition, 

 and also in the Hydrographical Atlas, will well repay close 

 examination. Sailing among these islands, over eighty in 

 number, — only four of which are over twelve feet high exclu- 

 sive of the vegetation, — two or three are almost constantly in 

 sight from the mast-head. 



The small amount of habitable land on these reef-islands 

 is one of their most peculiar features. Nearly the whole sur- 

 face is water ; and the land around the lagoon is but a narrow 

 rim, the greater part of which is usually under water at high 

 tide. This fact will be rendered more apparent from the fol- 

 lowing table, containing a statement of the sizes and areas 

 of several islands, with the amount of habitable land. The 

 measures are given in geographical miles. 



The ten islands here enumerated have an aggregate area of 

 ,852 square miles, while the amount of actual dry habitable 



