Continuity: "Night of the Bubbling Death": When West breaks into the hacienda, the double windows he enters by have quite a bit of glowing light behind them. Yet when he climbs into the room, it's completely dark inside.

Revealing: "Night of the Bubbling Death": Artemus takes off his coat and is wearing smoke canisters strapped to his back underneath. But the close fit of his jacket in previous shots reveals that the device wasn't there until just before he began removing the coat.

Factual error: "Night of the Underground Terror": The small round table in West's railcar parlor has a flip-over top, with secret maps hidden on the underside. The wine decanter and glasses all stay attached when it flips. But impossibly, when West turns the tabletop back over at the end, there's a full cup of coffee sitting on it.

Continuity: "Night of the Bubbling Death": When Grigsby first approaches the stolen U.S. Constitution, it's under glass (we can see the light reflections). But seconds later he lifts the paper without removing the glass, which has disappeared. It's back later, when West must cut it to retrieve the document.

Factual error: "Night of the Arrow": The soldiers toss Artemus into the cell, slam the door and walk away. But they never produce a key or lock the cell door. He's somehow locked in anyway, though.

Continuity: "Night of the Arrow": President Grant's cigar keeps getting longer, shorter, and longer again as he gives West and Gordon their special assignment aboard the train.

Revealing: "Night of the Jack of Diamonds": During his fight with West, Sordo the bandito, who has a gray beard, is suddenly several years younger with a dark brown beard, thanks to the substitution of a stunt double.

Continuity: "Night of the Bubbling Death": West uses a glass cutter to retrieve the US Constitution, which was lying flat under a covering sheet of glass. But when he reaches in and pulls the document free, it is no longer flat, but is rolled up.

Factual error: Throughout Series: No one ever explained just how West and Gordon were able, in the 1870s, to send and receive telegraph signals from a moving train, without any wire connection.

Continuity: "Night of the Arrow": West and Gordon leave two champagne bottles and four glasses sitting on the table when they walk away to answer the door. When they return, the bottles and glasses have all completely changed positions by themselves.

Continuity: "Night of the Arrow": When Artemus pours the president a drink, the glass is only 1/4 full. When Grant picks it up, however, it's suddenly 3/4 full.

Factual error: "Night of the Lord of Limbo": At the end, Vautrain tells West and Gordon to go through the door on their right. The door is on the camera's right, but is on West's and Gordon's left.

Plot hole: Throughout Series: West's private train had only two cars. The foremost was sleeping quarters; the rear car served as dining room and guest parlor. But with no livestock car and no second train following, West nonetheless always had his trusty black horse with him wherever he went.

Revealing: "Night of the Underground Terror": During the climactic fight scene, James West's famously tight trousers rip apart in the crotch, amply revealing his very 20th-century white jockey briefs. A few shots later, that rip mends itself and the pants are split (much more decorously) down the right outer seam instead.

Continuity: "Night of the Bubbling Death": The dust left on West's jacket after the fight changes patterns several times, then disappears altogether when he enters the building. A shot of his feet shows us that his formerly dusty boots also polished themselves.