As they excavate archaeologists find both artifacts (objects) and features (non-moveable parts of a site such as walls, wells, and pits). Postholes are one type of feature that archaeologists often find at Jamestown.
Many of the buildings at James Fort were made of wooden posts set in the ground. Over time, the post decayed and left a dark stain in the soil. Archaeologists find these circular stains while they are excavating. By “connecting the dots,” archaeologists can figure out how large a building is!
Sometimes, archaeologists discover very big postholes. This posthole was over 3 feet deep! Archaeologists found one like it in the north bulwark that they think marks exactly where James Fort’s original flagpole stood!