CORALS AND CORAL ISLANDS. 227 
CHAPTER III. 
FORMATION OF CORAL REEFS AND ISLANDS, AND CAUSES OF 
THEIR FEATURES. 
I. FORMATION OF REEFS. 
I. ORIGIN OF CORAL SANDS AND THE REEF-ROCK. 
Very erroneous ideas prevail respecting the appearance of 
a bed or area of growing corals. The submerged reef’ is 
often thought of as an extended mass of coral, alive uniform- 
ly over its upper surface, and as gradually enlarging upward 
through this living growth; and such preconceived views, 
when ascertained to be erroneous by observation, have some- 
times led to skepticism with regard to the zodphytic origin 
of the reef-rock. Nothing is wider from the truth: and this 
must have been inferred from the descriptions already given. 
Another glance at the coral plantation should be taken by 
the reader, before proceeding with the explanations which 
follow. 
Coral plantation and coral field are more appropriate ap- 
pellations than coral garden, and convey a juster impression 
of the surface of a growing reef. Like a spot of wild land, 
covered in some parts, even over acres, with varied shrub- 
bery, in other parts bearing only occasional tufts of vegeta- 
tion in barren plains of sand, here a clump of saplings, and 
there a carpet of variously-colored flowers in these barren 
fields—such is the coral plantation. Numerous kinds of 
zoophytes grow scattered over the surface, like vegetation 
