Hey, Roger, have you read the 2014 book: Supplying Custer: The Powder River Supply Depot, 1876? Apparently a few years ago this archaeology digging guy found some old stuff in a river bank in Montana that came from a military supply depot used by Custer. The buffalo bones date the site to before 1890, because as we all know bison were all killed from the Great Plains by 1890, and a gun cartridge dates the site to after its manufacturing date.