Valley Of The Dinosaurs

A brontosaurus thrusts himself into the families' cave to reclaim the "forbidden fruit" that Greg disobediently has broght home.

A host of giant army ants invade the Valley, eating everything in their path.

An earth shift causes the men to be split from the women as they enter the Valley of the Three Giants while in search of a passage reputed to lead out of the Valley.

John correctly guesses that a shock wave from a nearby volcano foreshadows a larger catastrophe. The villagers must figure out how to divert the lava flow before the volcano erupts.