“Not a stranger this time,” Perry went on, “but a cyclone.” “Which I’m feelin’ grateful you let me get away first.” “This is a real cyclone,” the boy continued, “and we’ll suppose that it tore the shanty in half, cutting it clean across the floor, the way cyclones often do, taking half of it away in a cloud of dust, but leaving half of it as straight cut as though you’d passed a knife through a layer cake.” “And I returns to that scene of desolation?” “You do,” Perry assented. “And there you see the half of the shanty and the floor, which is in three layers, the bottom one of pine shavings, the next one of oak, and the top one of boxwood. Then, since you remember how you used to work, you know that there are pine animals carved with a jack-knife in the bottom layer, oak animals carved with a jack-knife in the lower part of the oak layer, oak animals carved with a chisel in the top part of that layer, and boxwood animals in the top boxwood layer.” Antoine nodded his head approvingly. “That is a very good figure,” he said, “I think Mr. Round-up Dick can follow that.” [Illustration: _Courtesy of American Museum of Natural History._ FINDING THE EOHIPPUS. The Wasatch formation, in the Bad Lands of Wyoming, in which lie skeletons of the Dawn Horse.] [Illustration: _Courtesy of American Museum of Natural History._ EOHIPPUS, THE FOUR-TOED HORSE. The Dawn Horse, the earliest horse so far known, size of a large fox, adapted to low-lying and wooded ground.] “Clear as the barrel of a six-shooter a foot from your nose,” agreed the cowboy. “Now, Dick,” Perry went on, “the real thing was a good deal that way. When Nature first started to make a horse, it came out like a four-toed creature not much bigger than a fox. The rocks that Nature was making at that time, which we call Lower Eocene, we can liken to the pine shavings. So you see, wherever you find Lower Eocene rocks you’re likely to find skeletons of that little four-toed horse, just the same way as any place in that layer of pine shavings you’d be apt to find the horses whittled out of pine. We call that horse an Eohippus.” “That’s a whole lot of handle for a critter no bigger’n a fox!” “‘Hippus’ means ‘horse,’ and ‘eo’ means ‘dawn,’” explained the boy, “so the Eohippus is the Dawn Horse, or the Dawn of the Horse.” The cowboy rolled a cigarette. “Which I’m admirin’ your lay-out a heap,” he said, “you’ve sure got a double cinch-strap on that horse stuff.”