With the Dinosaurs (Andrew Lost Series #11) by J. C. Greenburg, Jan Gerardi
Andrew, Judy, and Thudd have escaped primordial Earth only to find themselves surrounded by huge–and hungry!–dinosaurs. Meanwhile Uncle Al is still stranded in the Ice Age. Somehow Andrew, Judy, and Thudd must fix their time machine and rescue Uncle Al–before he becomes a human ice cube! Kids, parents, and teachers love this series–kids for all its gooey grossness, and teachers and parents for all the fun science and great discussion points!
From the Trade Paperback edition.