by Jonathan Brisendine – CART Archaeological Technician
To start off, let me pose a few questions. What are good data? This is a question we as archaeologists get a lot. If we find nothing, is that a bad thing? What do we do if we find artifacts but the context is mixed due to human interference such as plowing? Let’s first answer the overall question of what are good data. The answer is all data are good, either be it through the presence of in context features or the absence of artifacts entirely.
However what happens if there is an artifact presence yet the context is mixed due to years of plowing? In the past when one came upon a plow zone it was typical to just write it off and strip the ground down past the plow zone in order to get to undisturbed soil. Many studies have been conducted in order to test the validity of this practice. (Hind 2014) It was found that while, yes, in the process of plowing the context was mixed; however, not all data were lost. The most effected data were what I would call the vertical data or the depth at which the artifacts were deposited. Vertical data usually follow the Law of Superposition, where evidence of the earliest occupants of that area being the deepest buried and the most recent occupation being the closet to, or at, the surface.
Within plow zones, it has been found that larger artifacts were most often found near the surface. This can lead to a misinterpretation of the data in both pre-colonization and post-colonization period occupations. For pre-colonization this is seen in the role of importance that is given pottery and stone tools such as projectile points verses smaller debitage and faunal material which can help play a more vital role in distinguishing distinct activity areas. However with post-colonization the variety of artifacts that can be easily dated are far more numerous in addition they are also more identifiable when smaller fragments are found than that of artifacts of a Native American origin.
Another type of data that we can gather from a plow zone or in any stratigraphy is that of horizontal data. While the vertical data doesn’t move as much as the horizontal the impact is greater within the vertical as the horizontal data still remain in relative context verses the time of deposition. For example within a colonial home one would find a concentration of cookware style ceramics within the kitchen. After years of plowing the artifacts have traveled from their original location but the artifacts still remain within a relative concentration, thus identifying the location of where the kitchen would have been. (See blog post Through the Looking Glass.)
Archaeological methods and practices are an ever changing field of new techniques, practices, and ways of viewing and interpreting data. While methods and ways of viewing and interpreting data may change one thing remains constant: that data are data. This applies to that of artifacts within plow zones where the context has been mixed due to human interference or to the lack of artifacts entirely.
Hind, Jill and Gary Jones, Klara Spandl. 2014. “4G2 Ploughzone Archaeology – Historic Environment Record Case Studies: Use of Ploughzone Data.” Oxford Archaeology South. Num 1. Oxford Archaeology, Oxford