The Incredible Petrified World (1960)

The Incredible Petrified World is a 1960 science fiction film directed by Jerry Warren and starring John Carradine and Robert Clarke. The film is about four explorers who travel down into the depths of the sea and get stranded in an underwater cavern. While waiting to be rescued, the group runs across a crazy old sailor named Matheny who's been living in the cave for years. They find a rotting skeleton of another sailor, whom they learn was murdered by Matheny. The rest of the story deals with their attempts to escape and return to the surface world.

The film was actually completed by Warren in 1957, but remained unreleased until it was distributed in April 1960[3] on a double feature with Warren's Teenage Zombies.

For more info click on the link: https://en.wikipedia.org/wiki/The_Incredible_Petrified_World