There is a costuming error when Tobin (John Wayne) calls home. He's shown wearing a badge, but it is on the wrong side of his chest; it should be over his heart on the left side, not the right side.
At the 46 minute mark in a fight John Wayne swings at the other man but very obviously doesn't come close and the man falls back anyway.
During the chase, just before Ruby's horse goes down, a highway bridge is visible in the distance between the trees.
When the sheriff takes Tobin into custody, he "slaps" the handcuffs on him. Handcuffs of the time did not ratchet through in a complete circle and had to be opened before placing them on the prisoner.
When Tobin (John Wayne) places Zanti's unconscious body on the horse, Zanti reaches out for the horse.