Modern city blocks often give no indication of what lies just a few inches below their surface. Asphalt and lawns can hide the remains of buildings, or the wells and privies used by long-gone inhabitants. The first step in excavating a city block is to strip away the modern surface. Archaeologists often use backhoes to remove layers of asphalt, gravel and rubble to reveal the historic ground surface beneath. This is called Open Area Excavation because it exposes large areas of the historic ground surface all at once. DIG DEEPER: When Archaeological Deposits are Found After Construction Begins
Surveyors are then brought in to mark out the boundaries of the historic building lots, making for an easier job of locating the privies and wells that usually lay close to the back fence. Archaeologists, working with shovels and brooms, clean the dirt surface of loose soil and rubble. Sometimes they find the tops of brick foundations, or the dark smudges of organic-rich soil that mark the location of old privies and wells.