178 CORALS AND CORAL ISLANDS. 



the top of the beach, were believed by some to be keeping 

 patrol on the ramparts of a kind of fortification. This decep- 

 tion arose from the dazzling whiteness of the coral sand, in 

 consequence of which, the slope of the beach was not distin- 

 guished in the distant view. 



The emerged land beyond the beach, in its earliest stage, 

 when barely raised above the tides, appears like a vast field of 

 ruins. Angular masses of coral rock, varying in dimensions 

 from one to a hundred cubic feet, lie piled together in the 

 utmost confusion ; and they are so blackened by exposure, or 

 from in crusting lichens, as to resemble the clinkers of Mauna 

 Loa ; moreover, they ring like metal under the hammer. Such 

 regions may be traversed by leaping from block to block, with 

 the risk of falling into the many recesses among the huge 

 masses. On breaking an edge from the black masses, the 

 usual white color of coral is at once apparent. Some of the 

 blocks, measuring five or six feet in each of their dimensions, 

 were portions of single individual corals ; while others had the 

 usual conglomerate character of the reef-rock, or, in other 

 words, were fragments torn by the waves from the reef-rock. . 



In the next stage, coral sand has found lodgment among 

 the blocks ; and although so scantily supplied as hardly to 

 be detected without close attention, some seeds have taken 

 root, and vines, purslane, and a few shrubs have begun to 

 grow, relieving the scene, by their green leaves, of much of 

 its desolate aspect. 



Both of these stages are illustrated on the greater part of 

 coral islands. 



In the last staoje, the island stands six to ten feet out of 

 water. The surface consists of coral sand, more or less dis- 

 colored by vegetable or animal decomposition. Scattered 

 among the trees, stand, still uncovered, many of the larger 



