Friday, August 15, 2008

How Archaeologists Look at the Chicken and Egg Question

How you look at the which came first, the proverbial chicken or the egg conundrum, depends on your discipline. This post reveals the mysteries of how archaeologists look at the problem of which came first. This issue is important for archaeologists because often where something is relative to something else may the best (perhaps the only clue) to when it was. Knowing when, in turn, may reveal a lot about what it is and the other things people really want to know after spending hours digging in the dirt. So the where and the when--the chickens and the eggs-- are very important to archaeologists.

Last Saturday's workshop was designed to teach us how to properly sort the chicken and egg question in an archaeological way because the handful of amateurs gathered in Castle Hill Heritage Centre are supposed to be able to do a proper job of archaeology after the real archaeologists leave.

First Andy Heald, Managing Director, terrified us with such home truths as "archaeology is destructive." Once something is removed from a site without properly designating where it was or drawing the site correctly or any of the other careful steps, then we have destroyed it forever. Then he encouraged us with brave words about how we could save our heritage and it was ours to preserve. Caught somewhere between numb terror and glowing enthusiasm, I tried to follow his lecture about how to do it.

Here's what the white board looked like after his lecture:

My nerves were rapidly overwhelming my enthusiasm. He assured us that it would become clear after we did it ourselves and he would show us the magic tool to make it all sensible. We broke for a cup of tea. We were a very quiet group. Even in Britain there are limits to just how much wisdom or comfort you can get from a cuppa.

He introduced us to the Harris Matrix. I have seen Gantt charts and PERT maps and mind maps and the old fashioned maps of the things you can see. A Harris Matrix is a map and an index rolled into one. The first tricky bit of understanding the matrix for me--the index bit--is that the numbers on the matrix are assigned as you delve through the layers in the dig, so the number does not mean much relative to the other numbers, except 000, which means turf or the bit on top that you pull off to get to the mysteries below.

The other tricky bit about the numbers is that they have to mean something across the entire site. Everyone knows that 000 is turf. That is good for starters, but then if someone in trench A gets into a layer of clay, they need a number for that because it is something different. They cannot call their clay layer Fred, which was personally what I wanted to call ours, because Fred may show up in other trenches (or may not) and so it has to have a number that will ultimately make sense not only of my own personal trench but also for the site as a whole.

OK, so the numbers have to be assigned by someone with more than a one trench perspective and delvers need to remember to get a number assigned. How does a digger know when to jump up and say I need another number, please because I just moved into something different?

Context. A context represents some action or interaction that invites more looking into. The Harris matrix is the device for recording those contexts. The virtue of the Harris matrix is that it identifies contexts (if done right, occurring across the site), and it shows the relative position of those contexts. It's that relative position that gets us back to the chicken and egg conundrum.

After lunch, we came back to practice what we had learned about in the morning. This is what our "site" looked like. To the untrained eye, this is stuff sitting on a shelf made up of a countertop. But with some discussion, my teammates and I discovered that we had several contexts--wall, counter top, photo. Within all these contexts were important clues about chronology: the wall had to come before the picture, for example.

So thanks to the knowledge from the morning and a little help, we resolved the chickens and eggs for one countertop using our shiny new toy and constructed our very first Harris matrix.
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Andy took a photo of all of us proudly clutching our Harris matrices to mark the rite of passage along the way to becoming proper archaeologists.

Now, in addition to remembering all we have been told about soils, pottery, and coring, we just have to master small finds register, data structure reports, context sheets, and photographic register--black and white and colour.


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