Continuity mistake: When Jessica has gone over the cliff in the dark we can see that she is wet, dirty and her hair is plastered to her head and is under her collar. The shot changes to show how precarious her place is on the side of the cliff. However, in this shot, the stuntperson's hair is quite dry and over the collar. Also noticeable is the change in shape of the rock. When she falls at night, she falls onto a very flat and rock - in the morning, it is a different shape entirely.
Continuity mistake: Near the end of the movie when Jim is tying Bess to the back of the cart, it shows his horse. The horse has sweat patterns on him but no lather on his face. In the next scene when Jim mounts his horse, the horse is drenched in sweat and has flecks of lather all over his face and nose. The following scene as Spur drives away, the lather on the horses face disappears.