According to The Illustrated Dinosaur Movie Guide: "This was (Willis) O’Brien’s original attempt to interest RKO in a big budget stop-motion project, to be directed by Harry O. Hoyt. A submarine expedition is shipwrecked on a volcanic South American island. The sailors, along with the survivors from a wrecked yacht, discover a lost world populated by prehistoric monsters (created by Marcel Delgado). A test reel was produced, in which a character named Hallett (Ralf Harolde) kills a baby triceratops and is subsequently chased by its much larger parent. These scenes also include Snooky the chimpanzee. More than $100,000 was spent on this project by the studio before it was cancelled. However, it led directly to O’Brien’s involvement in King Kong (1933)."