It’s time for Mystery Monday! Here is a fossil that can be found in Arkansas, but is completely different from anything I’ve put up here before. Let’s see if you have the paleontological fiber needed to solve this puzzle, or do you lack the stomach for it? 🙂
paleoaerie 
My first inclination was to say some kind of tree trunk, but your hint has me thinking it’s digested plant matter from stomach contents or coprolites of a large mammal.
One of the things I always tell my students is to never change an answer unless they have compelling reason to do so. Would it make a difference if I mentioned that it is thought that the reason so much coal developed during the Carboniferous Period was that there was not much of anything that could digest cellulose, so terrestrial plants too a looong time to decompose?