1st ed. - New York : Dial Books for Young Readers, c1997.
Book — 32 p. : ill. (some col.) ; 22 x 27 cm.
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.