They take notes as every inch of soil is excavated. These observations, along with maps and photographs, are scientifically more important than objects. Artifacts and other clues can tell us about the past only if they are collected in a controlled, scientific way. Without good records artifacts are like a jigsaw puzzle with key pieces lost. They had only uncovered remains of temporary camps.
Archaeologists dig carefully.
They first establish a reference point, called a datum, from which the locations of all artifacts and features are ultimately measured. Archaeologists lay a numbered grid over the site based on the datum. This system makes it easier to record the location of each recovered artifact and feature. Artifacts are objects that are made or used by man. Features are signs of human activity, such as post molds, building foundations and fireplaces.