We were working today in a construction site that has already been built on three times, most recently a townhouse development that stood from 1970 to 2010. You wouldn't think that much would survive here, but we found two areas where the original topsoil had been buried under fill before all that construction started.
So we took off the fill with a backhoe and dug some hand units in the buried topsoil
And found stuff like this. In the top picture, a sherd of Potomac Creek pottery, likely 600 or 700 years old, and next to it a quartzite spear point. This looks to me like a type called Morrow Mountain, which would make it 6,000 or 7,000 years old. In the bottom picture another sherd of late prehistoric pottery and a screen full of the stuff from the buried topsoil: prehistoric pottery, stone flakes, and nails, pottery and glass from a farm that stood here in the 19th century. All of this came from the same level, so it doesn't have a lot of scientific importance, but it sure was cool to find.