Mansell imagines dinosaurs in various contemporary environments: Diplodocus causing an urban traffic jam; Deinonychus in competition with the rats at a dump; Stegosaurus browsing in a pasture; Elasmosaurus menacing a rowboat; Bagceratops nesting on a child's bed. A wealth of intriguing details in the cartoon-style illustrations dramatize size and behavior while making delightfully logical extensions from the premise. Not a new idea, but carried out with unusual verve, humor, and respect for the substantial amount of information conveyed. (Picture book. 4-10)