Friday, December 7, 2007
Limits of Shovel Testing
Tuesday the team was shovel testing in front of the Chimney House and Stagg Hall. While screening the soil from STP 409, they recovered a Lincoln cent, then a Late Archaic projectile point, and then another Lincoln cent. Sometime during the process they also recovered a sherd of British Brown stoneware.
The pennies are dated 1942 and 1948. The point is several thousand years old, and the ceramic sherd is an 18th-century import (probably from before the American Revolution). Together this group of objects illustrates one of the principal limitations of digging shovel test pits that are less than 1½-ft in diameter: we can't control for stratigraphy. That is, we aren't sure whether these four artifacts came from one layer of soil or several, nor do we know if the point came from the lowest portion of the soil profile, the sherd from the middle, and the two pennies from the upper. We can be sure that they represent aboriginal, 18th-century Euro-American, and 1940s occupation of the immediate vicinity.
We do not know whether the layers of soil representing those occupations retain their integrity; that is, whether or not they have been disturbed by utility installation, cultivation, or driveway construction. That is why we need to dig larger units (3 ft by 3 ft, or 5 ft by 5 ft) in which we can carefully remove one layer, or stratum, at a time and collect the artifacts separately for each. Hopefully, we will begin digging such larger units in the Spring.