“Of course,” the professor answered, “that was what we counted on. When we reached the bluffs, we found numbers of bones of giant reptiles strewn along the base, tumbled from the rocks above, as gradual weathering had exposed them, but most of these were broken and so badly weathered that other collectors had passed them by. The outlook was not good, but after a few weeks we found parts of the skeleton of the Diplodocus and the Brontosaurus.” “Let’s see,” said Perry thoughtfully, “the Diplodocus was the long-limbed one and the Brontosaurus was a heavy brute.” “Fairly heavy,” agreed the professor, “the one we found would have weighed at least thirty-eight tons when alive. The skeleton was sixty-six, nearly sixty-seven feet long. One of our men discovered it and it took the whole of one summer to extract the skeleton from the rock, here, on the Laramie Plains, and ship it to the Museum. In the New York workshops it took another two years of steady work, all day long, every day, to chip away the rock from the bones, to cement the brittle and shattered petrified bone, so that it would be strong enough to bear handling, and to restore the missing parts of each of the broken bones. And then, Perry, the mounting of the skeleton had not been begun.” [Illustration: _Courtesy of American Museum of Natural History._ UNEARTHING A SAUROLOPHUS SKELETON. Crested dinosaur of the Cretaceous period, allied to Trachodon, skull seen in foreground.] [Illustration: _Courtesy of American Museum of Natural History._ UNEARTHING A DIPLODOCUS HIND LIMB. Amphibious dinosaur of the Jurassic Period, found at Big Bone Cabin quarry.] “I can see how that would be,” the boy exclaimed, “I didn’t cut my Pteranodon entirely away from the rock, and just to get it partly cleared away was an awful job.” “Mounting that big skeleton was unbelievably hard,” the professor continued. “No museum had ever before attempted to mount so large a fossil skeleton, and you see, Perry, the bones were so fragile that they could not even bear their own weight, much less the weight of the skeleton. Nearly every separate bone had to be specially treated and hardened so as to be rigid. Then came the question as to the way in which the bones were to be articulated together. No one had ever seen a living Brontosaurus, of course, and so there was no guide as to what he looked like. The bones were there, but bones aren’t a safe guide by themselves.” “I don’t see why not,” remarked Perry. “Suppose you found the bones of a frog, but no one had ever seen a frog or anything that looked like one! You might set the animal up with those long doubled-up legs quite straight, so that he would look as though he were on stilts.” “That would sure make a queer-looking beast,” said Perry, laughing.