Trying to find out what my Indian artifact is?

I have a stone tool of some sort that was found in a field in Catawba County NC, so probably came from Catawba Indians. It is smooth,crescent shaped, with rounded ends. It has these indentions across it that look like finger marks or something. Also, there is a small edge on one of the rounded parts that looks smoother, more worn than the rest of the tool. I have googled and googled and cant really find anything exactly like it. It is about 6 inches long from end to end. It probably weighs around a pound.
ok, here are some pics :

http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=374978602&albumID=1170896&imageID=15868135
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=374978602&albumID=1170896&imageID=15868137