As much as two hundred and fifty-three million years ago, the most incredible beasts roamed this earth. They ruled supreme on the land, under the water, and in the air for some one hundred million years before their time came to an end. Now, all these years later, we study their bones--and the earth's memory of their bones--to learn as much about them as we can. For years, humans have marveled at dinosaurs and have strived to learn more about these...