Revealing mistake: The professor has a blowout, but all four tires on the car are fine. (02:04:30)
Revealing mistake: At a certain point we see the arid, dry Santa Monica Mountains of Los Angeles in the upper left of the picture with a huge high-tension electrical tower at the summit. The film is set in 1912 in Iowa, a green, rainy state which is also completely flat, with no mountains. Then again, we see the arid, dry Santa Monica Mountains in the upper right. (00:08:27)
Revealing mistake: When Ransom and Hallie Stoddard are riding the train back to Washington at the end of the film, pay attention to the view out the window as Hallie responds to Ransom's suggestion of returning to Shinbone. When the conductor brings the spittoon and talks to them, the same exterior footage repeats from when Hallie started to speak. (02:01:30 - 02:02:15)
Revealing mistake: When a girl is shot in the back with an arrow she falls on her face. When she's turned face up, the long arrow is gone.