You have got so far now that you know what fossils are, and where they may be found. You know that they are the small and large pieces of the “puzzle of life”—of all sorts of different shapes and sizes—and you know that they are scattered about the Earth, deep down in coal-mines, on the tops of mountains, at the bottoms of rivers, in deep caves, and under the sea. The patience and industry of clever men have been well spent in gathering together all they can find, and arranging them in museums for our instruction, and making a history of them which is more wonderful than the Arabian Nights, and more beautiful because it is all _true_. And, though you may think it strange that I promise to show you creatures more marvellous than those of the fairy tales, I shall keep that promise faithfully. We shall find no Genii with wonderful lamps and magic rings, because they never really lived, though it gave us much pleasure and amusement to read about them; but we shall see what God, the greatest Genius of all, has done by means of His magicians—the laws of Nature. These magicians have built up high mountains and dug out valleys, and sent mighty rivers sweeping down to the sea, and even filled up oceans with sand and chalk, and buried ancient forests deep down under sea and land. They worked with fire, and air, and water; not quickly, but with such strength that nothing could resist them, and they gradually moulded the Earth into the beautiful thing it is, so that In contemplation of created things, By steps we may ascend to God.—_Milton._