In the wise words of Dr. McMillan, what separates an archaeologist and a random guy digging holes is the process of diggings and documenting the units properly in order to make interpretations about the site; “our interpretations are only as good as our data” and if the unit is dug incorrectly, the data will be bad. Archaeologists dig two main types of holes, Shovel Test Pits (STPs) and Test Units. The focus of this blog post is on test units. Test units are usually done after STPs and are placed based off the results of STPs where an archaeologists hypothesize a site is located.
Last week, I started (and completed!) a test unit with my field partner, Lilly Salamone. To lay in the unit, we need to place four nails in the shape of a square on the ground. Each nail should be exactly five feet away from each other. Luckily, two grid nails had already been placed earlier using a transit and we could use their location to place the last two nails. To do this, we set up a math problem (yuck!) using the Pythagorean Theorem to figure out what our diagonal measurement of the square will be so we can correctly measure out the square. To spare you all from the math, the diagonal measurement of the triangle should be 7.07 feet. Using two measuring tapes we carefully measure the diagonal for the third point, once we find the place 5 and 7.07 meet, we drive a nail into it to mark it and repeat the process for the fourth and final point. Once that is completed we tightly string the unit to give us boundaries to dig. Now, we can start doing the fun stuff: digging!
Once the top soil is cleared, Professor McMillan had us practice “schnitting” which is an important technique (and not what I hoped was a pastry break), where the archaeologist lightly grazes the soil to evenly dig the unit and keep it level throughout. This is honestly kind of difficult, especially if the soil is bad (luckily we had the “best” soil, a sandy Tidewater soil that cuts like “butta”) but gets easier with practice. While schnitting, we began cleaning the walls and making them straight and clean. Professor McMillan had us do this with a spade to get the big portions done and then we went through and trimmed the roots with scissors and cleaned the wall with our trowel. After schnitting to subsoil, we carefully trowel the unit to fully reveal the subsoil and any features present on the unit’s floor. Eventually, you will have to get out of the unit to finish troweling because you can’t leave footprints inside the unit so you have to reach out and scrap the remaining parts of the floor clean. We had to be careful because sometimes we left what Professor McMillan calls “mouse poops” inside the unit, which are tiny pieces of dirt and the unit should be perfectly cleaned. Once the floor is cleaned we take pictures to document and score the features inside the unit. Scoring is essentially outlining your feature. Our unit had some features, all of which were plowscars and root stains. Overall, I think it was a fun experience and I think it was exciting to see the progression of the unit as we dug it. My favorite part about this unit is the lack of poison ivy and how easy it was to dig the soil. We mostly had quartz and quartzite flakes and shatter in our artifact assemblage but we also had a few pieces of ceramics, including Native American pottery and a piece of Staffordshire slipware which is odd for a Native American site but could’ve been the product of trade or an intrusive artifact from a different group of people who occupied the site at a different date.