Thursday, July 20, 2017

Reaching the Plow Zone

Gary helping a group of students prepare
 their pit for wet screening
Hello everyone, my name is Morgan Powers and I am a senior at Western Michigan University. Tuesday morning I had the pleasure of working with one of our wonderful staff members, Gary Thompson, who taught me how to prepare the floodplain for a day of excavations. We arrived thirty minutes early, which meant thirty whole minutes of peace and quiet in which we were able to start unloading the trailer and make sure the water pump was working properly before the rest of the crew arrived.
Student hard at work searching
for artifacts using the wet screen
              Once they arrived we quickly settled into our routine. My pit partner, Crystal and I were able to finish leveling our one by two meter unit to fifteen centimeters below datum before lunch with enough time left over to start mapping our unit in plan view. Our map included the big roots, dimensions, and soil changes as well as soil types. After mapping our unit my pit partner and I began to descend another five centimeters and then prepared to wet screen. At the Fort St. Joseph floodplain, wet screening does not occur until we reach the plow zone, but because our pit had evidence of human activity near the base of the alluvium, including bone fragments, seed beads, and calcined bone (burnt bone), and a ton of roots, it made it difficult to determine if we were still in the alluvium or the plow zone. Due to this we got the go ahead to begin wet screening which involves dumping a bucket of soil taken out of our unit onto a 1/8th in mesh screen. Once on the mesh screen, the soil is sprayed down with a water hose to remove extra sediment and allow us to see the pebbles, roots, and artifacts more clearly. As we are working we are constantly on the lookout for anything that resembles an artifact. This could include items such as bone fragments, gun flakes, daub (chunks of baked clay), lead shot from muskets, and so much more from the eighteenth century. The purpose of wet screening is to ensure us a better chance of seeing extremely small artifacts that might otherwise be hidden by dirt and accidentally tossed aside.
Once the artifacts have been recovered through wet screening they are set aside to dry and will later be taken to the lab to be cleaned more thoroughly and identified/analyzed. The field procedures as a whole allow students and anyone interested to learn more about life at Fort St. Joseph during the eighteenth century.  

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