A woman behind me picked up another piece and noticing the flat edges and the fact they fit together, correctly identified these pieces as pottery. Odd stuff (coarse and uniform, even in cross section) and strange to find in this picked-over ruin. Likely recently kicked out by the animal digging and I'm guessing it's early and primitive. The archaeologist with us is a pottery expert but other than being surprised I didn't hear a conclusion about what type it is.