CORAL REEFS. 29 



is. The Coral-builders have been erecting that wall ; 

 but though they have been at work upon it for many 

 thousand years, they have not yet succeeded in bring- 

 ing it to the sea-level, except at two or three points, as 

 I have mentioned. They are not however discouraged, 

 they are far more patient than little boys and girls ; 

 more patient even than men, and they will go on, 

 adding little by little to their wall, till they have joined 

 it to the mainland of Florida. 



But they cannot do this all alone, other agencies 

 must help them ; and in order to understand how this 

 is, we must look a moment at those islands lying within 

 the outer wall, and at the space that divides them from 

 the mainland. Those islands are part of a coral wall 

 exactly like the one outside of them below the water, 

 and the islands are those parts of it which have reached 

 the surface, and on which a soil has been formed by 

 the collection of sand, mud, broken shells, coral, sea- 

 weed, &c. There, as on the circular islands of the 

 Pacific, trees and flowers grow, and people live ; and if 

 you were to see some of the gardens of Key West, 

 that is the name of one of these islands, with their 

 tropical flowers of the most brilliant h les, their cocoa- 

 nut trees, their banana trees, and their delicious fruits, 

 you would hardly believe that on th s spot, not very 

 long ago, the waves washed over the li ttle Coral-build- 

 ers. There are, as you see by the woo I-cut, several of 

 these islands, all formed in the same way, by those 

 parts of the inner coral wall that have risen above the 

 surface and have become covered with soil. Betwec n 

 these islands and the mainland, the present coast of 

 Florida, all the space is filled by mud-fl.its ; that is. 



