An archaeological lab can be a fascinating place to work. Much of my time in lab has been spent taking heaps of dirty, unidentified artifacts from an excavation and making them clean, labeled, and carefully stored. In the midst of all the glass sherds and metal flakes are intricate pipe stems, beautiful porcelain, and complete pairs of scissors. These are interesting pieces to handle, and make processing the less exciting objects bearable.
But then there’s cataloging.
Cataloging artifacts is crucial to their usefulness and existence in a lab. Categorizing and officially recording all artifacts in a consistent and exhaustive list allows them to be studied, compared, and accounted for. Putting objects into the catalog, while tedious, can still be interesting when it comes to small finds or other unique pieces, but it becomes rather challenging when it comes to more common rubble.
A pile of plaster, perhaps?
This is precisely what I came across last week, and I had no idea where to begin! I briefly supposed I could catalog all fifty-some pieces under one entry as “plaster”, but that would not be very helpful. When cataloging artifacts, we want to be as precise and descriptive as possible so that each artifact is easier to locate and research. It would seem that “white, crumbly building material” would suffice for a description, but there is much more to plaster than what meets the untrained eye!
When an archaeologist is confronted with any number of artifacts, one of the best ways to sort and describe them is through a process called typology. Much like a tree diagram, typology splits artifacts into smaller and smaller groups until a pile of architectural debris becomes small sets of useful information.
When it came to plaster, the first type I sorted them into was whitewash, plaster, and whitewash and plaster. As you can see in the picture below, plaster is made with a thick, rough layer, and covered in a thinner coat of whitewash that is visible on the walls it covers. There are often a few more layers in between, but they’re trickier to clearly identify.
The next type is lath marks vs no lath marks. Lath is the term used for thin strips of wood that serves as the base for a plaster wall. While plaster is still wet, it is shoved through the lath, which anchors it in place. Though wooden lath itself doesn’t survive in the archaeological record, its imprint in the plaster does. Most larger pieces of plaster in the pile had lath marks on it, either in the form of wood graining, or a sharp right angle where the plaster molded over the edge of some lath.
After lath marks, the next visual distinction is (purposeful) scratches in the plaster. These scratches are often done to help another coat of plaster stick to the previous layer. This can be kind of tricky to pick out, but if I saw a deep groove on any of the pieces, I set them aside.
As you may have noticed, while typology is a great method to make sense of a seemingly mundane group of artifacts, it’s not a perfect system. In order to make typology work, you have to choose a hierarchy of types. While this works pretty well for the major categories, like whitewash and plaster base, it’s more difficult to prioritize sub-categories, like lath and scratch marks. For example, I now have scratched pieces of plaster in four different categories: both lath-marked and non-lath-marked under the categories “plaster” and “plaster and whitewash”. A bit confusing, right?
Even with its disadvantages, though, typology got those pieces cataloged for me. Several dozen bits of seemingly identical plaster took on a whole new appearance in my eyes. Plaster “says” a lot more to me, now that I know what to look for. By forcing one to sort and categorize, typology gives information and detail to every artifact subjected to it. Cataloging may not be the most exciting part of lab work, but thanks to typology, it’s made a whole lot more sense.
