The colony thrived for a long time, and accumulated quite a stock of limestone. But at last a change came: there was a great rush of muddy water from the land, and all the Favosites died, leaving only a stony skeleton to prove that industrious Polyps had ever existed there.
This skeleton remained undisturbed for ages, until the earth began to rise inch by inch out of the water. Then our Favosites' home rose above the deep, and with it came all that was left of its old acquaintances the Trilobites, who were the ancestors of our crabs and lobsters.
Trilobite
Then the first fishes made their appearance, great fierce-looking fellows like the gar pike of our lakes, but larger, and armed with scales as hard as the armour of a crocodile. Next came the sharks, as savage and voracious as they now are, with teeth like knives. But the time of these old fishes and of many more animals came and went, and still the home of the Favosites lay in the ground.
Then came the long, hot, damp epoch, when thick mists hung over the earth, and great ferns and rushes, as stout as an oak and as tall as a steeple, grew in Nova Scotia, in Pennsylvania, and in other parts of America where coal is now found. Huge reptiles, with enormous jaws and teeth like cross-cut saws, and smaller ones with wings like bats, next appeared and added to the strangeness of the scene.
But the reptiles died; the ferns and the rush-trees fell into their native swamps, and were covered up and packed away under great layers of clay and sand brought down by the rivers, till at last they were turned into coal, forming for us, what someone has called, beds of petrified sunshine. But all this while the skeleton of the Favosites lay undisturbed.