Now you see we have come to a reptile that can fly, but, excepting for its wings and some of its bones, more like a crocodile than a bird. A little further on we find another curious animal in the oolite rocks, which is much more like a true bird than the pterodactyl, because it had feathered wings. It is called the _Archæopteryx_, which means “ancient wing,” and I have given a picture of it on the same page as the pterodactyl, so that you may compare them together. The blade-bone and “merry-thought” of this creature were exactly like those of a bird, and so were the feet and legs, which would enable it to walk easily, or perch on the branch of a tree, but the tail was long and many-jointed like that of a lizard, with a fan of feathers growing on each side of it, and short feathered wings. Then it most likely had teeth like a lizard, and there were short claws at the bend of the wings. This bird-reptile was about the size of a crow, and was the first we know of with feathers, and the limestone rock has preserved it most beautifully through all the long ages which have passed since it flitted over the land of the oolite period.[12] Later still than these, there lived in America, about the time the chalk was formed in England, two strange birds called _Hesperornis_ and _Ichthyornis_, both of which had teeth in the jaws. The former was an immense fellow like the penguin, with short wings, and the latter was about the size of a pigeon with large feathered wings. They are finding more of these curious creatures every now and then in America. Some are without teeth, and have a horny bill like that of a real bird, and in other ways more nearly resemble living birds; still they have not lost the appearance of reptiles in their principal bones. [Illustration: VI. _Pterodactyl_ (_Wing-finger_). _Archæopteryx_ (_Ancient-wing_).] I have been particular in describing some of these fish-lizards and bird-reptiles; because they, or their near relations, were the principal inhabitants of land and sea from the end of the coal period to the end of the chalk, though there were of course swarms of fishes and shell-fish; but I ought to tell you that even so early as this there was at least one animal known which suckled its young ones, and this was a small insect-eating creature not larger than a rat, of the same family (called _Marsupial_) as the kangaroo of Australia, which carries its young ones in a pocket or pouch in its skin.