Let us imagine ourselves back in that age, as Pixies, or water-sprites. Suppose that we are in a warm, shallow, almost waveless sea, over which the sunshine pours, warm and mellow, through thin haze. We are sitting on a ledge of coral, and from every tiny limestone tower about us opens and waves a radiant creature, purple, gold, green, or crimson. Among the corals grow the tall and stately stone lilies, rolling back their petal-like valves, and waving forth long white plumes. We gather tiny live things from the water and offer them to the stone lilies, and they grasp them in their snowy hands. But now we see a monster coming towards us, a new creature such as we have never seen before! It swims strongly, has a thick skin, great jaws filled with big teeth, and we perceive that it has its bones inside its body, not outside, as the crustaceans do. It sweeps past a bed of pretty little lingulæ and crops off fifty of them at a mouthful! It darts up to our lovely stone lily, and bites it from its pearl-white stem! Yonder comes a crab swimming along at ease, a prophecy of a king-crab, that will come many ages after. The fish-like monster takes him at a mouthful. We Pixies are angry at this devastation; we cry, “We hope you will try to eat a trilobite[12] and choke yourself!” But here comes an unlucky trilobite, and the new monster crushes it in its great jaws! It would eat us, only we are Pixies, creatures of myth, mere bubbles. As it is, we hide in our coral groves, and weep over our lost lingulæ and stone lilies. These fish-like creatures reign as kings. They multiply and devour, and in the Devonian age, which comes next, they become more like true fishes. This Devonian age comes with mighty changes. We Pixies feel the sea-beds rock with earthquakes. We fly to the rivers, and find the land rent with volcanoes. We hasten to the crests of the waves,--for the torrents of lava rush along the shores and far out into the ocean,--and we see the Afrites laughing to find vast plains of land where waters had been. We hope that all these convulsions have destroyed the greedy, cruel fish. But no; we go deep into our sea-homes, and find most of the crabs and nautili and stone lilies gone, and the fish more abundant than ever! And now we Pixies feel that the new age has come, and we rise to the sea-surface to look about, and we find new land in many lovely islands, and there are vast swamps full of reeds and club-mosses. Green lowland jungles laugh in bright sunlight, among warm, clear, blue seas, where the corals that we love grow to their greatest glory. No more soft-shelled crustaceans and trilobites: have the fishes eaten them all? If we make an excursion to the land to see if any fairies live there, we find no flowers, but there are very beautiful trees.