Professor Ladue smiled. "It lived a great many thousands of years ago. Nobody knows how many thousands of years, although they will tell you very glibly. They don't know anything about it except that it was a long time. I know that. This little lizard is a kind that nobody has ever discovered; nobody except me. It is _my_ lizard. It must be known by my name. What do you think of that, Sally?" "It must be very fine," Sally murmured, "to discover things." "At that far-off time," the professor continued, "there were lots of great horrid creeping and flying things. Even my little lizard may have been able to fly. See! These seem to be the beginning of his wing bones. There are some bones missing, so that I can't tell, yet, whether he had wings that would bear him up. But probably he had. Probably he had." And the professor relapsed into a thoughtful silence. "Father," said Sally presently. She had been thinking and her interest in the skeleton was more active than it had been. The professor looked up. "Any question that Miss Ladue has to ask," he observed, "will be cheerfully answered, provided that I know the answer. If I do not know the answer, and have the courage to say so, I trust she will not regard me as wholly ignorant of the subject." Sally gave vent to a chuckle which was entirely unexpected; entirely unexpected by herself, at least. "Father," she asked, as soon as she had managed to suppress her chuckles, "then could your little lizard fly up high?" "Yep," he answered; "like a pigeon. Or, more probably, he flew more like a bat than like a pigeon." "Right up into the tops of the trees?" "Right up into the topmost branches of the coal trees." "The _coal trees_!" "The coal trees. Fed on the fruit. Large lizards customarily ate furnace coal, middle-sized lizards ate stove coal. Little lizards ate chestnut coal." Sally burst into an uncontrollable fit of laughter. In all her experience of her father, she had never known him to be so amusing. "And the littlest lizards?" "Ate pea coal," replied the professor promptly, "and the tiniest babies ate buckwheat coal. Very nourishing, chestnuts and peas and buckwheat. Cracked it with their teeth." Sally was still giggling. "Seriously, Sally," said the professor, with a change of manner, "by the coal trees I meant the trees which have become the coal we are burning in the stove and the furnace and to make steam. I see no reason to doubt that this little lizard could fly up into the tops of the trees. Perhaps he actually alighted on some tree which we now have down cellar in the coal bin." "Oh!" cried Sally. "Let's suppose he did. And what did he see from his topmost branch?" "Very little," replied the professor, "except treetops and a swamp or two." "Well," said Sally, "it's rather disappointing. But I wish I could have seen it."