After Whitey and Louise have been playing in the river, when they walk away from it how wet they are changes between shots. When the camera is behind them they are barely wet, Louise's hair still has volume and her shirtwaist sleeves are still puffed, but when the camera changes to in front of them they are soaked through, Louise's hair is flattened and sticking to her face, and her shirtwaist sleeves are clinging to her arms.
Several episodes show purebred Australian Cattle Dogs which did not exist in the USA in the 1880s. This breed wasn't brought to the USA from Australia until the 1950s or 80 years later. A mixed breed mutt would be more accurate to the old West.
Correction: The dog in this show is not an Australian Cattle Dog - it is an Australian Shepherd, which would be appropriate in this show because the breed originated in the Western United States around the 1840s and were popular working dogs even then.
Correction: The dog in this show is not an Australian Cattle Dog - it is an Australian Shepherd, which would be appropriate in this show because the breed originated in the Western United States around the 1840s and were popular working dogs even then.
In a flashback, young Roy hears the story of the hanging of Black Jack Ketchum, who was actually hanged in 1901, well after the time in which the series is set.