The Ghost of Slumber Mountain 1918

Synopsis:

In a dream Uncle Jack looks through a magic telescope owned by the ghost of a hermit and sees what life was like millions of years ago, including a battle between prehistoric monsters.

Directed by: Willis H. O'Brien
Written by: Willis H. O'Brien & Herbert M. Dawley
Runtime: 16 minutes
Tagline: These giant monsters of the past are seen to breathe, to live again, to move and battle as they did at dawn of life.
Cast:
Herbert M. Dawley
Herbert M. Dawley
Uncle Jack Holmes (uncredited) 
Willis H. O'Brien
Willis H. O'Brien
Ghost of 'Mad Dick', the Hermit (uncredited) 
Alan V. Day
Alan V. Day
Jacks Nephew 
Chauncey A. Day
Chauncey A. Day
Jacks Nephew