Monday, December 16, 2013

Boerner Family Cemetery Project: Research Design and Excavations

This is a continuation of my series on the Boerner Family Cemetery Project (BFCP). For previous posts, see here and here.

I had two main goals for the Boerner Family Cemetery Project (BFCP):

  1. To find the grave shafts without disturbing the graves themselves
  2. To provide a meaningful learning experience for the students in Intro to Archaeology

Finding the grave shafts without disturbing the graves is relatively easy. Beneath the dark topsoil (very dark and rich in this area which had not been farmed in over a hundred years), there is a substrate of yellowish clay. Once the topsoil is stripped away, we can see where the clay beneath has been dug through. Theoretically, at least, the outlines of the grave shafts will be obvious once they've been exposed.

Arial view of the site before (below) and
after (above) the destruction. The graves
were in the grove of trees shown. The
half-acre site can be seen as a lighter
rectangle in the picture above. The
large white circle is the pit where the
gravestones and remains of trees were
buried after removal from the site.
 (Photographs courtesy of Scott Boerner)
It would have been easiest to mechanically strip the topsoil using a backhoe, but there is a higher chance of damaging human bones with mechanical stripping, especially since the original destruction of the site may have disturbed some of the graves (the giant cottonwood tree that was in the middle of the cemetery was pushed over, and that must have caused disturbance underground.) Also, it would have been difficult to get heavy machinery out to the site, since the fields surrounding the cemetery are not owned by the Boerner family, and the man who does own them asked that we not drive across his land. Finally, my students wouldn't have learned nearly as much from watching a backhoe operator as they did by digging themselves.

Julius Boerner had originally laid aside half an acre of land for the cemetery. We do not have a map or overview photograph of the site from before its destruction, but family members could tell us that the graves were mostly in the southeastern quarter of the site. We have arial photographs showing the layout of the grove of trees which, again, tended toward the southeastern quarter.

We had a lot of graves to locate, and only limited time to spend in the field (in the end, we only have two weekends for this phase of the project), so we concentrated our efforts in the southeast. We placed three narrow trenches about 1.5 meters apart, running north-south across the cemetery. Since most Christian graves of that period were laid out east-west, these north-south running trenches had the best chance of intersecting the grave shafts.

The students mastered the use of shovels while digging the trenches nearly a meter (3 feet) below the current surface. The trenches bottomed out when they hit the clay. In the southern half of our trenches, the clay was consistent, a clean, unbroken surface of yellow. But to the north, it became mottled, broken up, mixed with the dark earth. Had we found the graves?

The patch of dark earth covered a wide area and had no clean or straight edges. My students found their feet shifting beneath them as they encountered small pockets of empty air beneath the soil. The final clue came from the many large roots that our shovels encountered. We hadn't found the graves, we'd found the area where the trees had grown through the clay to reach the water below.

So grave shafts weren't the only things to break through the clay. The trees had as well, especially the large cottonwood that had once stood at the heart of the cemetery. Tree roots and grave shafts look very different, but with only a narrow slice of the ground visible at the bottom of the trenches, it was hard to tell the sharper, more rectangular outlines of a grave shaft from the more shapeless outlines of a tree's root system. We had to connect the trenches, opening up a wider area so we could see the difference.

The last day of the excavation (everything happens on the last day of an excavation!), we opened up the area between the trenches, in the northern-most section of the area where we worked. This created a larger area where, visible against the mottled clay, we could see two grave shafts (neither of which was fully exposed by the excavations). Both appear to be large enough for for adult burials. However, further exposure may make this clearer.

Although we screened all materials from the area in the northern part of the trenches, no artifacts or human bones were found. I admit this was a surprise because the mottling of the top of the clay layer suggests significant disturbance due to tree roots and, presumably, the uprooting of those trees. I had expected to find remains, especially of small bones. This was not the case, however, and that's a good sign that the graves have not been disturbed.

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