Having previously only done clay-animated shorts depicting dinosaurs, Willis H. O'Brien would by this period in his life attempt something more ambitious of which this film is the result. It begins in live-action as a man-played by this film's producer Herbert M. Dawley-starts telling his two pre-teen male nephews a story as it segues to him and a fellow traveler on a canoe with a dog setting up camp. His friend tells of an old hermit named Mad Dick (O'Brien) who has a telescope that allows him to see prehistoric creatures. So those creatures come to life on screen as we see some dino fights. I'll stop there and just say Willis improves himself here as he attempted more realistic renderings of the dinosaurs instead of the cartoony ones previously. While this film was a mix of live-action and clay animation, they're not done together in the same scene as the split-screen method hadn't been developed yet. Still, it does the job as well as one could expect at the time. Too bad that only an 18-minute version exists, instead of the 40-minute one that was originally released. What makes this a really important work for O'Brien was the fact that it led him to be hired to work on something even more ambitious: the original filmed version of Arthur Conan Doyle's The Lost World...