THE PACIFIC OCEAN. 



281 



lime grandeur, nor the peculiar loveliness of the 

 atolls. The rocks are crystallized carbonate of lime, 

 supposed to have been originally coral, " but, by 

 exposure to the action of the atmospheric air, to- 

 gether with that of the water percolating through 

 them, the loose particles of calcareous matter have 

 been washed away, and the whole mass has become 

 harder and brighter." In the islands named Atiu 



Crystal Islands. 



and Mauke, the latter of which was discovered by 

 Mr. Williams in 1828, that gentleman found seve- 

 ral extensive caverns, having a stratum of crystal- 

 lized coral, fifteen feet in thickness, as a roof. In 

 one of these exquisitely beautiful caverns he walked 

 about for two hours, and found no termination 

 to its windings. This circumstance, together with 



2a2 



