If the top soil layers of a site have been mixed by more modern activity, heavy machinery can be used to more efficiently expose the deeper deposits and features. A Gradall operator carefully peels back the upper layers while an archaeologist watches closely for signs of features. Once a suitable amount of overburden has been removed, the field crew uses a hand excavation technique called "schnitting." They scrape away loose soil with flat shovels, revealing features that contrast with the surrounding subsoil (left).