Dinosaurs, Dinosaurs

Barton's economical book does not scrimp on details or ebullient hues. In colors straight out of a crayon box he provides children with a genuine ``first'' dinosaur book. The endpapers provide a vivid glossary of dinosaurs, with names and phonetic pronunciations underneath each picture. And then the sweet text: ``A long time ago there were dinosaurs. There were dinosaurs with horns and dinosaurs with spikes . . . . There were fierce dinosaurs and scared dinosaurs.'' That particular line is illustrated with a black cloudy sky and jagged yellow lightning; the simple expressions of fear on the dinosaurs' faces will reassure readers that even these mightiest of creatures could have been afraid of the same things children are. Ages 3-6. (Mar.)