Devonian, Mahantango fm., Eastern WV. (average size thumb)
Not much here to go on. I barely saw the edge of it so I dug it out ... just to see that it went nowhere.
By comparing photos, it looks like a single pleura from an eldredgeops trilobite.
Am I close ?
If it is, its the first one I've seen here among quite a number of cephalons and pygidia.
Been very busy with work, hope to get a chance to look around a bit toward the weekend.
Cheers.