Ben McGrath had a fascinating piece in the New Yorker last week on the Ramapough Mountain Indians who live in New Jersey. I can't excerpt the piece because it's behind a curtain. But one interesting point came when McGrath was basically trying to suss out the ethnic origins of the Mountain Indians. It basically turned out that there was very little Native American blood among them, and that they were, essentially, a mix of blacks and whites. But to not have to deal with white racism, they consciously decided to start calling themselves Indians.
Forgive me, that may be a bit rough, but that little bit of passing was particularly depressing. It's worth checking out the piece. There's a lot going on--race, modernity, civil liberties, environmentalism. It's a gripping read.