Time's Secrets, Unearthed
You probably think that archaeology is all about artifacts, all about obsidian spear points, crystal skulls and gold idols.
If you think that, you are wrong. Archaeology is all about dirt.
I know this because I spent a day last week as an archaeologist, a day that I only now have gotten out from under my fingernails and probably will never wash out entirely from the knees of my jeans.
To an archaeologist, dirt is the cosmic timekeeper. It's the hands on the clock, the squares on a calendar. It's the medium that tells you this piece of pottery is older than that one.
Dirt is so important that archaeologists don't do anything so vulgar as actually dig it. They sort of gently coax it aside: "Please, Mr. Dirt Clod, would you kindly move?"
I know this because Heather Bouslog , assistant archaeologist for the Maryland-National Capital Park and Planning Commission, invited me to help excavate a Civil War-era site not far from the Chesapeake & Ohio Canal.
We live in an archaeologically rich area. Prehistoric peoples roamed the landscape. Settlers came, wars were fought, towns grew and fell and grew again. And at every turn, humans left traces of their lives in the all-embracing dirt.
On Wednesday, Heather, her boss Jim Sorensen , 10 other archaeology buffs and I hiked to a location in the woods near Montgomery County's Muddy Branch. We pulled back the black plastic sheeting that protected the areas under excavation. String attached to spikes enclosed 5-by-5-foot squares.
The site has been fairly productive. Close to 30 Union regiments camped there over the course of the war. They looked for Confederate soldiers. One hundred forty years later, we were looking for what was left of them.
Artifacts found in the same layer of dirt come from the same time, so it's important to know exactly what kind of dirt you're working with.
"One of the things you develop is an aesthetic sense of dirt," said Mike Robinson , 60, a volunteer who worked beside me.
If you can roll dirt into a sticky ball, it has clay in it. If it makes a raspy sound as you squeeze it between the fingers, it has sand. If it's soft like talcum power, it has silt. Then we compared our dirt to a set of color swatches. It was "strong brown" on the Munsell scale.