Producer Hal Roach ventures into dinosaur country--with the help of spectacle expert D.W. Griffith--to create this ambitious prehistoric adventure. It's a sweeping saga of inter-evolutionary romance as Tumac (Victor Mature), of the Neanderthal-like Rock People, falls for beautiful Loana (Carole Landis) of the more advanced Shell People. In addition to their disapproving tribes--and the problem of Tumac's bad table manners--the young lovers must contend with erupting volcanoes, earthquakes, prehistoric monsters, and other hazards of life on a still-forming planet, including Tumac's angry father (Lon Chaney, Jr.). A modern professor (Conrad Nagel) patiently explains their trials and tribulations in a clever framing device. The dinosaur scenes (using actual lizards filmed in miniature backdrops) were recycled in numerous cheap monster films in the 1940s and 1950s.