(Most recent reply listed first)
Joel's mystery fossil looks like a Mucrospirifer brachiopod,
from the Devonian period. Don't know the species. Hope this helps!
Cheerio, ... James C.
That mystery is definitely a spiriferid brachiopod, and since
Tulsa is sitting on and totally surrounded for many miles in all
directions by Pennsylvanian age rocks, it is almost certainly Neospirifer
or a closely related genus. We have Mucrospirifer up here near Buffalo
in the Devonian and that's pretty flat and different texture, and
the other large Devonian spiriferids also look quite a bit different.
Nice representative specimen. ...- Rick B