How deep do you dig?

After the capital of the colony was moved to Williamsburg in 1698, the James Fort area became farmland. This is fortunate for archaeologists because the area did not evolve into a functioning city. It's unfortunate because the plows disturbed the strata of the soil, digging down and turning it over. Another unfortunate, but interesting feature of James Fort is the fact that it was used as a Confederate fort during the Civil War. The Confederate soldiers moved the earth into mounds, as a basic defense facing the James River. During this process, they shifted tons of artifacts. It can be hard to pin down a specific date for a discovery if the context is ruined.

That's why the wells were such great finds. Everything was in context. The layers were undisturbed, with the oldest artifacts further down. If you find something that you can date, you can know for certain that everything below it is older than that date, and everything above it is younger. There are other sections of the fort area that are undisturbed, but for the most part, the plow zone and Confederate earthworks are accounted for. The archaeologists are sure to take into consideration the fact that the artifacts found in these layers are out of context. However improbable, it is possible that a Civil War soldier had a 17th century artifact from somewhere and buried it during the 19th century.

Underneath the miscellaneous upper layers (like the old gravel road and church rubble we are currently digging through), the Civil War fort, and the plow zone is the fort period layer. This level is undisturbed, with no bits of brick or gravel. The archaeologists don't know quite how deep this layer is until they find it and until they dig further down and hit the native horizon, where prehistoric artifacts can be found. This fort period layer is what the archaeologists are Jamsestown are looking for. This layer is closely examined for features and artifacts as the soil is scraped away with trowels. We stop digging when we find features (areas of the earth that are visibly or physically different, evidence of the remains of a post hole, grave, foundation, etc.) or reach the native horizon.