One hundred and fifty million years ago at a place called Como Bluff, in what would become the state of Wyoming, ancient rivers left deposits of multicolored mudstone. In the spring of 1877, some inquisitive bipedal vertebrates discovered in these red, green, and gray deposits the fossilized bones of extinct vertebrates, both small and almost unimaginably large, and the ancient life of western North America began to be revealed.
These famous bone beds of the Morrison Formation, whose rocks are exposed from Wyoming down through the red rock region of the Southwest, have yielded one of the most complete pictures of any ancient vertebrate ecosystem in the world. Among the discoveries here have been a great many of the most important finds of Late Jurassic dinosaurs such as Apatosaurus, Allosaurus, and Stegosaurus. But dinosaurs comprise barely a third of the more than 90 types of vertebrates known from the formation. In fact, the Morrison contains a surprising variety of life forms: crocodiles and turtles, frogs and salamanders, dinosaurs and mammals, clams and snails, and ginkos, ferns, and conifers.
This volume, aimed at the general reader, tells the story of the life of this ancient world as scientists have so far been able to reconstruct it. Even after more than a century of exploration, the Morrison continues to yield new discoveries about a time so different from our own that it almost seems imaginary.