(I haven't seen National Treasure: Book of Secrets yet, but I've got a pretty good guess about the plot, so if you don't want any story spoilers, here's your warning. Turn back now.) In addition to the creepy Mount Rushmore picture and the webpage that lets you put the heads of your dearest loved ones on the sculpture, the official National Treasure: Book of Secrets website has posted a timeline of Black Hills and Rushmore history. It's pretty standard stuff - when gold was discovered here in 1874, when Congress authorized the project in 1925, when the carving actually started in 1927 - but one entry on the list is a little goofy. It reads: "1876 - Following the Battle of the Little Bighorn, gold reportedly worth $375,000 is lost along the shores of the Bighorn River, never to be seen again." It's a bit like that Sesame Street game - one of these things doesn't belong. Given that the Little Bighorn Battlefield is about 300 miles northwest of Mount Rushmore, this is the only entry on the timeline that doesn't deal directly with the history of the sculpture. I think it's a pretty safe assumption that this story of lost treasure factors into the film's plot. There may be some connection with George Custer, who was on the loosing end of that particular battle, but who also discovered gold in the Black Hills two years earlier. There may also be some connection with Charles Rushmore, the New York lawyer after whom the mountain was named. At the same time, it's pretty clear from the movie trailers that the characters are exploring inside the Hall of Records, the tunnel behind Mount Rushmore's heads. Given that construction on the Hall of Records didn't start until Borglum began carving the memorial in the late 1920s, I'm not sure how they can explain the intervening 50 years. As for Custer's lost battlefield treasure, I ran into some information about it while doing research a few years back. The article, first published in Treasure Cache Magazine, is no longer online, but I had printed out a copy and filed it. Let's hear it for paper. The basic idea is that the payroll of the Seventh Cavalry, along with the soldiers' personal items (watches, lockets, rings), were never recovered from the battlefield, and the artifacts haven't surfaced in the 131 years since. Historic records indicate that a pay wagon of $25,000 in silver, gold and bank notes accompanied the soldiers into the field, apparently because commanders were worried their men would blow it all on booze, gambling and girls if they were paid before their march. Inflation and the rising price of precious metals would put the current value of the treasure near the $375,000 mark noted on Disney's site. A fun story, and certainly one that could have helped inspire the movie.