Hickory Bluff Project
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Issue 7: Why Do Archaeologists Dig Square Holes?
Take a quick look across the Hickory Bluff site and you'll see lots of little orange flags marking spots on the ground, and a series of square holes with string around the edges. It looks like an archaeological site. So, why do archaeologists always dig square-sided holes? Well, it's mainly so that they'll know where they are.
Space is a key idea in archaeology. Where something is found is as important as what it is or how old it is. The location of an artifact within a site tells us its association, what it was related to, what it goes with. It's like a puzzle, we have to figure out what pieces go together before we can start to assemble them. For example, if we find charcoal from a campfire or hearth that has a radiocarbon date of 1000 B.C., we want to know whether other artifacts found near the fire were from the same period or whether they were left by people who used the site much later. Or we may find pottery fragments and stone tools in another part of the site. If we know from the style of the pottery that it was made 700 years ago, we can determine that the stone tools are of the same age if we can tell from their locations that they were associated with the pottery.
So, knowing where you are on the site is very important. Sometimes small distances can be critical, and thus, exact and accurate measurements are made of every significant find. In that way, we can reconstruct the site later in the lab, on paper at the least. To make measuring like this practical at a site as large as Hickory Bluff, we create landmarks within the site. The corners of the excavation squares are the landmarks that we use for measurement. They are often called datum points, since they are the points from which locational data are collected.
The squares or excavation units are laid out precisely on a grid using surveying equipment such as a transit. The corners of each unit then have a unique identification based on their location relative to a central, or datum point. The horizontal positions of artifacts from the corners of the squares are noted, as well as the depths below the surface of the square, giving us exact information about where each artifact was found in relation to all the other artifacts at the site.
