pyle 
—— ain a | ‘\ 
iy [aT | | 
’ wh bP’ 4 THE COMPLETED ATOLL. 309 
~ Darwin’s theory, therefore, still remains as the theory 
af that accounts for the origin of atolls and barrier islands, 
which is not true of any other that has been proposed. 
Fringing reefs and isolated coral-reef banks may form in 
shallow water within the growing depths of reef-making 
corals, and on any kind of bottom. But atolls, barrier-reefs, 
and coral formations of great thickness require, as a rule, the 
aid of slow subsidence, —as has been true for nearly all the 
thick rock formations over the continents. 
V.—THE COMPLETED ATOLL. 
The atoll, a quiet scene of grove and lake, is admirably 
set off by the contrasting ocean. Its placid beauty rises to 
grandeur when the storm rages, and the waves foam and 
roar about the outer reefs; for the child of the sea still rests 
quietly, in unheeding and dreamy content. This coral-made 
land is firm, because as has been already explained, it is liter- 
ally sea-born, it having been built out of sea-products, by the 
aid of the working ocean. And so with the groves: they 
were planted by the waves; and hence the species are those 
that can defy the encroaching waters, and meet the various 
conditions in which they are placed. The plants therefore 
take firm hold of the soil, and grow in all their natural 
strength and beauty. 
Only an occasional coral island has a completely encir- 
cling grove, and is hence a model atoll. But the many in 
which a series of green islets surround the lagoon are often 
but little less attractive, especially when the several islets pre- 
sent varied groupings of palms and other foliage. To give per- 
fection to the coral island landscape there ought to be, here 
and there, beneath the trees, a pretty cottage or villa, and 
other marks of taste and intelligence; and now and then a 
