In 1947 Edwin Colbert and a team of scientists from the American Museum of Natural History discovered an important dinosaur fossil site north of Albuquerque, New Mexico, in a canyon on Ghost Ranch. In this single site, there were dozens and dozens of fossilized skeletons of small dinosaurs of the same species-- Coelophysis --that lived 225 million years ago. What caused such a large number of dinosaurs to die in the same time and place? Seven different scenarios have been put forth by scientists who have used the fossil evidence to try to solve the mystery. We see each one laid out here, along with the pros and cons based on scientific evidence, so that we not only get a sense of what might have happened, we see how paleontologists use the fossil record to reconstruct prehistory. (Ages 5-11)

Hundreds of dog-size, meat-eating dinosaurs suddenly perished 225 million years ago. Half a century ago, the bones of these Coelophysis were dug up in what is now Ghost Ranch, NM. Why did they die all at once? This book posits different answers--volcano? asteroid? poisoned water? mud? food?--and teaches en route how science evaluates hypotheses.