Wednesday, June 8, 2011

We play in the dirt for a living.

Dear Diary,

Yesterday, after laying out our units and mapping in the corner points, we started mapping out our surface artifacts on a drawn-to-scale grid. This morning, we finished that process and then proceeded to discover the joys of . . . paperwork.

But first, surface collection inside a unit: After we recorded our unit’s relative locations via a Total Station , we began a crawl survey inside the unit boundaries. Each piece of bone, shell, ceramic or lithic sitting on the visible surface was marked on a drawn-to scale map. Since our units are exact two meter squares, we can easily map the artifact’s location by measuring its distance to a vertical and horizontal edge of the unit.

After we were satisfied that everything visible was found (there are many artifacts on the surface, but hidden by grass or straw), we began the tedious but incredibly necessary process of paperwork. In our field journals, we began a list of lot numbers and artifact numbers. Along with basic location information, such as where we are working, what unit we’re working on, and what level we’re on in that unit, we also record any possible information that may be of use to future archaeologists. We don’t want another student fifty years from now puzzling over where a particular ceramic was recovered (because it’s often complicated)!

Such information includes the date, the size of the unit we’re working on (2x2 m), and the context or description of the lot (such as surface collection, plow zone, level one, etc.). We also record the soil type (such as silt, clay, sand, or some type of loamy mix of the any two or all three) and color (matched to a good old Munsell color chart) and a basic list of what we found (ceramics, lithics, bone, etc.).

Each ceramics or lithic we recovered on the surface was also given an ‘artifact number’ and description in the lot list, and was then bagged separately; bone and shell were bagged in groups together, and not given artifact numbers. Each bag requires its own separate tag with all the pertinent information recorded on it before being placed in a ‘master bag’ for that level, which also has its own tag; this is a purposefully redundant system that ensures that, under practically no circumstances will the provenience of the artifact be lost.

After the paper work stage (which took a couple hours), each group took corner and center elevations of their unit. To record the elevations, you first find the highest corner point; then, using a level and a long string attached to the corner pin, you can find the difference in elevation at the other corners. These are important for understanding the stratigraphy of the unit as you dig.

The next step is cleaning the unit before you begin digging. Cleaning a unit involves cutting – NOT pulling! – any grass, brushing back any loose straw, and generally making the dirt surface visible. A lot more surface artifacts were recovered during this stage, but since they weren’t previously visible in the crawl survey, they were just put together in the master bag.

Finally, after a unit is cleared, it’s time to begin the first excavations. We use flat shovels to shave off the dirt a few centimeters at a time. Since our first level is an arbitrary level of 10 cm, we’re not concerned with keeping the contours of the surface – this is because the field has been plowed, and most units have tire treds or plow lines running through them. These are artificial changes to the soil stratigraphy, and so we don’t follow them.

The loose dirt is then collected in our trusty Best Friend, Mr. Bucket, and then carried over to our sifters. Sifting allows us to pick out artifacts from the loose dirt that we missed while digging.

Artifacts recovered include things like shell, bone, ceramics, lithics and tiny beads - like above! We only had a little time to dig before our Field Director, Dr. Sampeck, called it a day – but it was great to finally start the excavations!

Cailin Meyer (ISU: Historical Archaeology Graduate Student)

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