TEAM PALEO : Last Dig Day

Often archaeologists discover most of their finds toward the end of the dig. It's a bit of a frustrating conundrum! On Gwen's last dig day, she took lots of pictures of a house the MSU team was excavating.

In a smaller pit feature, we found exposed bone, likely from a meal of a larger bird like the geese and ducks that still inhabit the nearby Emiquon Nature Preserve. Bones and scraps like this are tossed into a garbage pit where we find them today. Obviously, it is helpful to know what the people are eating, but quantity of materials also helps us know how many people may have been living there. For example, if we find large quantities of deer bones we know deer were abundant at that time. We might go further and see if they are using the bones to make tools, like needles, awls, hoes from deer mandibles and scapulae.
We also see a reddish chunk of sandstone in the lower right hand corner of the image. It was exposed to fire at one point, as the sandstone is red.

The morning weather was unsettled and scattered showers kept hitting the site. But the clouds cleared quickly and by ten in the morning, we were enjoying sunny weather. We can continue to dig during a light rain, with the use or tarps and tents (which also keep the glaring sun off of us on hot days). But we have to 'tarp up' the dig site in heavy rain. This means we must cover every inch of the excavated area with a large tarp, using sandbags to try to seal and secure the edges. Nevertheless, rain water will still percolate into the excavation. It is, after all, a big hole in the ground. Sometimes pumps must be used to siphon the excess ground water out of the excavated areas.

At the house, we see a cross section or profile of the excavation. Charred logs are easy to see- possibly a sign that the house building burned in a fire. Already removed from this section were 3 or 4 other charred logs.

This is a closeup of the image above, where we saw evidence of charred logs. You can see that the soil here is yellow and lighter in color than the surrounding soil. The lighter soil is the natural floor of the house when the original residents lived there. In other words, it is ground level. All the darker dirt on top is from the plow zone or A horizon fill- this is soil, organic material, artifacts, and naturally accumulating materials that fill in where the house used to be.
Usually, these homes were built by digging a basin into the earth, then building short walls around the edges. Imagine the classic 'sunken living room' in a modern house- except the entire house is sunken.

Here you see a large pit feature in the earliest stages of excavation. Across the approximate center is a string, which marks the diameter of the circular shape of the feature. The string provides a straight line, making it easier to know where to dig. You start by digging on one side of the string giving us a clean profile wall along the string.

This is the same pit feature as above, but digging has commenced. Digging occurs in 10 centimeter deep increments, creating levels that are clean scraped, mapped, and photographed for documentation. The reason for going down 10 centimeters at a time is so you can see the pit feature as it progresses down. This also saves the excavators and screeners from processing clay-like b-horizon soil that is not part of the feature.

Same feature, clean scraped and ready for photography- You can faintly see the edge of the feature where the darker soil meets a lighter, yellow soil, near the upper left hand side of the photograph. So where we see this soil demarcation, the edge of the pit feature is established.

Here is another example of bisection lines. This feature has not been excavated at the time of the photograph.

One of the MSU students excavated this feature- a post mold with the remains of the charred post still visible. You can see the bisected profile wall clearly here. Once the feature has been photographed, the charcoal is carefully removed and wrapped in tin foil to protect the friable material. Samples are sent to the lab for analysis of the type of wood used. It could also be dated for age.

A large fragment of decorated pottery- I found this in the pit pictured above.

This is an exciting find- burned roofing thatch that had fallen into the pit feature we were digging. Likely to be made from grasses, thatching was used for covering the roof of a structure- probably a home. Preservation in this pit is good, as charcoal often degrades easily.

Here we see the pit feature containing the charred roofing thatch. We can also see the straight bisection line dividing the pit in half, as well as the excavation boundaries. Each level is 10 centimeters deep, and like stairsteps. Of course, the pit would not have originally been dug in stairsteps- this is a result of careful excavation which shows the borders of the pit at each 10 centimeter level.

A photo showing the entire excavation block in which we worked. Our pit with the charred thatch is in the center of the image. In the upper left hand side is another large pit feature- you can see that the walls are almost straight down, rather than stepped. This is because the pit is deep and cylindrical in shape, where as the charred thatch pit is more shallow and the walls are bowl shaped. However, later in the dig we discovered that what we thought was a shallow bowl ended up being a six foot deep storage pit.