 | John Hughes Bennett - 1872 - 536 páginas
...other. Hence why those who live near the surface cannot exist a few fathoms deep ? A coral reef, then, is a structure built up from a definite depth, successively...ceases in its turn ; and so on, till it is completed. Suppose we have a slanting shore, and that at 600 feet dise from the shore the depth is 10 or 12 fathoms,... | |
 | John Clark Ridpath - 1898 - 528 páginas
...of the water. And while it is growing, this wall is all the time changing its builders. It isnotone kind that commences and completes the structure to...succession of reefs ; for the animals which begin to work live at that depth. They commence building a wall in that form : steep toward the ocean, slanting... | |
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It isnotone kind that commences and completes the structure to the summit. One kind does a part of the work, and then ceases ; another kind comes in and continues the work for a while, and ceases in its turn ; and so on till it is completed. Here we have... 