Visible crew/equipment: The scene where Martin and Ethan watch the Cavalry ride in through the river, a car or truck is seen driving up a road to the right and comes to a stop.
Other mistake: There is a scene where a dead Indian warrior is discovered. In this scene he is covered by a large flat piece of stone. When they pull away the stone you can see his chest rising and falling as the "dead" Indian breathes. Much easier to see when viewed in HD.
Continuity mistake: In the scene where John Wayne is looking down at the arrow that Look has left, his moccasin is all brown. In the next shot, his moccasin is partially opened on the side, revealing his sock.
Continuity mistake: After repelling the Comanche charge at the river, the three searchers continue on alone, three men, three horses. Yet, after Brad makes his suicidal charge, the next morning the two remaining gents have acquired a pack horses and gear.
Revealing mistake: In the scene right after they leave Scar's wigwam, when Ethan and Martin are speaking to each other around their camp you are able to see a small brown dot right above the sandy hills. This dot is the character Debbie's head while she is waiting for her cue before she runs in to the scene.
Factual error: The movie's beginning takes place in 1868, yet all the men pack cartridge Peacemaker Colts (not available until 1873) and model 1892 Winchesters (not available unti 1892).
Factual error: In the building where the wedding nearly took place, the kerosene Aladdin lamp is likely a 1932-1933 model 100 Venetian, far from the 1868 setting of the film.
Visible crew/equipment: In the scene where Scar is sitting with another renegade in front of a teepee, you can see the overhead lighting equipment very prominently.
Continuity mistake: After the fight between Martin and Charlie just before the wedding both fighters get extremely dusty and dirty. Then Mose appears after escaping from the Indians. While the rangers and searchers gather to hear Mose, Martin and Charlie are now in clean clothes and appear to be freshly showered.
Continuity mistake: When they find the dead Indian under the rock the red rag on his face is on and off in different shots. He is breathing when they remove the rock and he flinches when Bond removes the red rag.
Factual error: During the snow scenes, after finding Look dead, first a column of soldiers cross an icy river then a column of Native Americans. The woman on the white horse is wearing sunglasses. (01:00:18)
Continuity mistake: In the scene where they find the massacred cattle, Ethan tells Martin that the horses need grain and rest. Ethan and Mose ride by Martin in the next scene and Martin, whose horse is dead, tries to get a ride with Mose. Despite the fact that Mose and Ethan have horses that are galloping quickly, Martin arrives at the burning house the same time as them.
Continuity mistake: When the posse is having the gunfight with the Indians across the river, the river is flowing from left to right when viewed from the Indians' side, and it's also flowing from left to right when viewed from the posse's side. It should be flowing from right to left.
Continuity mistake: In the beginning when Martin is on foot and Ethan is approaching him on his horse with no gun in his hand, less than a second later he's holding his rifle out and obvious.
Continuity mistake: When they find the dead Indian under the rock the red handkerchief goes from his face to Ward Bond holding it.
Continuity mistake: At Martin and Ethan's camp Ethan keeps throwing wood on the fire and the wood is practically on Martin's bed. By the end of the scene the wood is nowhere near Martin's bed.
Continuity mistake: In the beginning of the movie when Aron opens up the seat of the barrel chair to hide the gold coins Ethan just gave him, both hands are visible and he is not smoking a pipe. In the next shot when he closes the lid of the hiding place he has a pipe in his mouth.
Factual error: The Mexican woman cooking in the canteen is using a modern aluminium pot.
Continuity mistake: In the canteen where they meet the Mexican guy and Mose, the tequila bottle changes from being round to being square.
Continuity mistake: When Laurie is reading the first letter from Martin, Charlie McCorry is sitting in the chair opposite her lightly strumming his guitar. The camera angle is facing him showing his fingers are wrapped around the fingerboard. As she keeps reading, the camera angle moves to behind his head and now showing Laurie's face. In the left side of the scene, Charlie's fingers are now on the side of his face slightly under the chin and his elbow is on top of the fingerboard. When the camera angle goes back to looking at Charlie, his hand is once again around the neck of the guitar.
Chosen answer: There was no cactus. A young inexperienced cavalry man, played by Patrick Wayne, constantly holds up his saber, which Ward Bond tells him to put away, before he hurts someone. After the battle, someone asks if he got injured by the Indians. Ward angrily replies "It wasn't the Indians" and looks at Patrick, who has a look of embarrassment.