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 Istanps. 
and Mauke, the latter of which was discovered by 
Mr. Williams in 1823, 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 
242 
