A turn of the century wild west show struggling to make a living in Mexico comes into the possession of a tiny prehistoric horse. This leads to an expedition to the Forbidden Valley where they discover living dinosaurs. They capture one and take it back to be put on display, leading to inevitable mayhem.
| Writing | William Bast | Screenplay |
| Directing | Jim O'Connolly | Director |
| Sound | Jerome Moross | Original Music Composer |
| Art | Gil Parrondo | Art Direction |
| Crew | Julian More | Additional Writing |
| Visual Effects | Ray Harryhausen | Visual Effects |
| Production | Charles H. Schneer | Producer |
| Camera | Erwin Hillier | Director of Photography |
| Editing | Henry Richardson | Editor |
