--_Professor Blackie._ SOME EARLY SETTLERS AND THEIR BONES But a farm where nothing but plants grow isn't much of a farm. Every good farmer knows that nowadays, and so he stocks his place with horses and cows and chickens and things. Mother Nature understood this principle from the beginning, and the plants and animals on her farm have always got on well together. For one thing the plant and the animal each help the other to get its breath. That is to say, plants, when they take in the air, keep most of the carbon there is in it and give back most of the oxygen, which is just what the animal world wants; while the animals, when they breathe, keep most of the oxygen and give back most of the carbon--just the thing that plants grow on. But the service of the animals to the plants is very important after they have stopped breathing altogether; since their flesh and bones, like the dead bodies of the plants, go back to enrich their common dust. The bones and bodies and shells of members of the animal kingdom, however, are far richer food for soils than is dead vegetation. The shell creatures of the sea to which we owe our wonderfully fertile limestone soils are--many of them--so small that you can only make them out with a microscope; while certain other contributors to our food-supply were so big that one of them, walking down a country road, would almost fill the road from fence to fence. I. MR. DINOSAUR AND HIS NEIGHBORS A STRANGE FACE IN THE MEADOW Now let's take a look at some of these big fellows. How would you like to have such a creature as the one at the right of this page come ambling up to meet you at the meadow gate of an evening when you went to milk the cows? Yet more than likely either this gentle animal, or some of his kin, browsed over the very field where now the cattle pasture, for he, too, was a grass-eater, and with an appetite most hearty. If you kept him in a barn his stall would have to be eighty feet long, and it would be necessary to fill his rack with a ton of fodder every third day. But, assuming there was a market for him in the shape of steaks and roasts, you would be well repaid; for, in prime condition, he weighed twenty tons. [Illustration: IN THE LAND OF HIS FATHERS] These monsters who ate grass, and other monsters who ate them, and still other monsters who lived in the sea, appeared comparatively late in the life of the world. [Illustration: NO WONDER HE NEVER WORRIED! Quite aside from the fact that he had so little brain to worry with, it seems highly improbable that the Stegosaurus ever felt any apprehension about attacks from the rear, in the frequent military operations which distinguished the times in which he lived. In addition to the horny plates down his back he had those horny spines which were swung by a tail some ten feet long.] TONS AND TONS OF ANCIENT BONES