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.
Revealing mistake: Throughout the film and specifically near the end after Jim has reclaimed Bess and the colt, there are visible horseshoes on the supposedly "wild" horses. While there would logically be a number of abandoned and escaped horses among the herd at any one time, those who joined them in a shod condition would not remain so very long in rugged country. Those born into the wild would never have worn shoes. Reason dictates there would be very few if any horses remaining shod at any one time.
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.
Visible crew/equipment: When the wild horses, known as the brumbies, come rushing past the ranch, a cowboy can be seen to the far left of the frame herding them into the channel between a tree in front of the home's front fence and the fence itself. It's an awesome, but complex shot, and the rider was meant to be out of frame, but the technical realities of a shot like that have him just inside the frame's edge.