Continuity: At the end of the film when Clark leaves to bring Marty home, he leaves on horseback. Yet when he arrives back home Clark, Marty, and the baby are all riding his wagon pulled by two horses.
Anachronisms: During the scene where Clark proposes to her in the rain, a bra strap is visible underneath her wet clothes. Bras weren't invented until the 1910s. A corset would have been worn.
Errors made by characters (possibly deliberate errors by the filmmakers): Aaron Claridge's eye blinked/twitched when Marty was looking at his dead body hanging over the horse.
Anachronisms: The covered wagon in the opening shot has safety chains that are chrome plated - a process not invented until well into the 20th century.