There's another alternative. I've been doing some work on the Amur region of the Russian Far East. There they have a lot of thrust sheets (with or without recumbent folds - mostly without), and I have been translating the Russian word "nadvig" as "nappe". Maybe I should be using "thrust sheet" - or just introducing "nadvig" into the English language (as a synonym of plaszczowina ?)- Steve Henley