Look at the edge and look for bits of grass with the clay is one way to help ID pottery or find someone that has collected a lot of it. I have a 5 gallon bucket of it so I have a pretty good idea if it is pottery when I find it.
Thanks for the responses and tips guys. I figured it to be pottery as it appeared to have grit temper and I have found pottery in the area before, but sometimes I'm just not sure. I found it in the water, like a previous piece. Thanks again for taking the time to reply.