Reap, we have you busy with our "trophy finds". Lol! Scuba, I'm not laughing at your find. I very well see the "ring" along the edge of this piece. I would have brought it in also. As you mentioned earlier, it may be a pecking stone or something along those lines. Good eye!! If we do not bring these in for questioning, we will never know. It's nice to have a sight with so much combined experience!Sorry, but I don't think it's a Discoidal. It looks more like a concretion to me. If you go to Google and look at concretions you will see a lot that look just like your piece. https://www.google.com/search?q=concretions&rlz=1C1TGIB_enUS534US584&tbm=isch&tbo=u&source=univ&sa=X&ei=vmlYU4eYHIqxyASZv4LICg&ved=0CDkQsAQ&biw=1366&bih=643#imgdii=_
Sorry, but I don't think it's a Discoidal. It looks more like a concretion to me.
If you go to Google and look at concretions you will see a lot that look just like your piece.
https://www.google.com/search?q=con...v4LICg&ved=0CDkQsAQ&biw=1366&bih=643#imgdii=_