The Ghost of Slumber Mountain is a 1918 American fantasy film, written and directed by special effects pioneer Willis O’Brien, produced by Herbert M. Dawley, and starred both men; Dawley played Uncle Jack Holmes, while O’Brien played the ghost of Mad Dick the Hermit.
Although most of the film itself is lost, it is often cited as a trial run for The Lost World. It was a box office hit, grossing over $100,000 on a $3,000 budget
Most of the plot is unknown; The Ghost of Slumber Mountain originally took up 3000 feet of film, equivalent to approximately 30 minutes, but Dawley cut it to only 11 minutes for unknown reasons. A restored version runs approximately 19 minutes.
In the version available today, Holmes (Dawley) is telling his nephews about an adventure he had in the woodlands around Slumber Mountain, near the Valley of Dreams. He found the cabin belonging to the late hermit Mad Dick, who Holmes’s friend Joe once saw carrying a strange telescope-like instrument.
That night, Holmes investigated the cabin and found the instrument. Upon doing so, the ghost of Mad Dick (O’Brien) instructs him to use it to look on the peak of Slumber Mountain. When he does, he seemingly looks back into the past, seeing a Tyrannosaurus and a Triceratops doing battle. The Tyrannosaurus proves triumphant, and after killing the Triceratops, somehow breaks the time barrier (unless the instrument had done that itself) and begins chasing Holmes.
But it was all just a dream…