"Mud," he said, "you are ugly and black, but you are also full of nice rich chemicals and all sorts of substances we need to make things grow. With the help of Air, and Rain, I am going to cover you with a beautiful carpet of green, so that you will not be ugly any longer." So the Sun turned his blazing rays on the soft mud and warmed it, and then a wonderful thing happened. Tiny living things, like plants, formed out of the chemicals in the Mud and the Water, and the Air, began to spring up, just as God had long ago planned. They were very small and weak at first, but after a while they grew stronger and stronger, until they had spread all over the Earth, wherever there was mud or dirt for them to grow in. And later on, because the Air was so moist and warm, the way it is in the tropics, and because the Sun was so hot, and there was plenty of Rain, the plants on the Earth grew to be very large and strong. There were ferns, like the little ones we see in flower-pots, as big as trees, and all sorts of tall, rank grasses, and vines, even at the North and South Poles, for in those days, before the Earth had cooled down the way it has now, the Poles were warm, too. For hundreds and hundreds of thousands of years these great ferns and other plants grew, and died, and fell back into the mud, and as they rotted they made more earth, for other plants to grow in, so that the earth-covering on top of the rocks grew thicker and thicker. In some places the leaves and trunks of these fern-trees got mashed down on each other in thick layers, and became harder and harder, until they turned to coal. Often, in coal mines, the miners will break open a lump of coal and find printed in its surface the exact pattern of the leaf of one of these great fern-trees, just as it fell, millions of years ago. While all this was going on, Mother Nature, having a little time to spare, came back to take a look at the Earth. It was one of the smallest worlds she had to look after, so she could not give it all her time. "It is doing very nicely indeed," she said to the Sun. "In eight or ten million years it may be ready for Man. But we must have some fish and other things first. Won't you please attend to it for me, Sun? I am very busy just now looking after some new-born stars in the Milky Way." "Certainly," said the Sun. "I will attend to it at once." So he turned to the Ocean. "Ocean," he said, "wouldn't you like to have some fish swimming about in you?" "Indeed I should," said the Ocean. "I am very big, and I have plenty of room for all the fish you can make."