60 CORAL FORMATIONS. 
seen from shipboard, standing spear in hand along the top of the 
beach, were believed by some to be keeping patrol on the ramparts of 
a kind of fortification. This deception arose from the dazzling white- 
ness of the coral sand, in consequence of which the slope of the beach 
was not distinguished in so distant a 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 incrusting lichens, as to 
resemble the clinkers of Mauna Loa; moreover, they ring like metal 
under the hammer. Such regions may be travelled over by leaping 
along 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 colour of coral is at once apparent. 
Some of the blocks, measuring five or six feet in each of their dimen- 
sions, were found to be portions of individual corals, while others have 
the usual conglomerate character of the reef-rock. 
In the next stage, coral sand has found lodgment among the blocks; 
and though so scantily supplied as hardly to be detected without 
close attention, some seeds have taken root, and vines, purslane, and 
a few shrubs begin 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 stage, the island stands six to ten feet out of water. 
The surface consists of coral sand, more or less discoloured by 
vegetable or animal decomposition. ‘There is but little depth of 
coral soil, although the land may appear buried in the richest foliage: 
and scattered among the trees, stand still uncovered many of the 
larger blocks of coral, with their usual rough angular features, and 
blackened surface. ‘The soil is seldom discoloured beyond four or 
five inches, and but little of it to this depth; there is no proper 
vegetable mould, but a simple mixture of darker particles with the 
white grains of coral sand. It is often rather a coral gravel, and 
below a foot or two, it is often cemented together into a more or less 
compact coral rock. 
One singular feature of the shore platform, occasionally observed, 
remains to be mentioned. Huge masses of reef-rock are sometimes 
found upon it, some of which le loose upon the reef, while others 
