Archeology has undergone radical changes since the time when an excavation was simply a mining of artifacts. Today, the removal of artifacts requires that the spatial relationships and context in which they are found be fully documented.
When an archeologist documents a find, he considers both vertical and horizontal relationships. Vertical relationships may yield information about the cultural history of the site, and horizontal relationships, about the way the site was used. In vertical excavation, the archeologist may use test units to identify and/or remove strata. Many archaeologists excavate sites in arbitrary levels, small increments of excavation, paying close attention to any changes in soil color or texture to identify various strata. In horizontal excavation, the archeologist may plow strips along the surface of the site to expose any objects lying near the surface. The excavation of a site proceeds by these methods until, layer by layer, the foundations of the site are uncovered. Often, excavation ends when sterile levels, strata without artifacts, are repeatedly uncovered.
Conventional excavation tools include, roughly in order of decreasing sensitivity, a magnifying glass, tape measure, pruning shears, bamboo pick, whiskbroom and dustpan, grapefruit knife, trowel, army shovel, hand pick, standard pick, shovel, and perhaps in some cases, even a bulldozer. Most of the excavation work is done with a shovel, but whenever fragile artifacts are encountered, the hand trowel becomes the tool of choice.