It does look like it has flaking on it. Have you posted this in the North American Indian Artifacts section? They will give you an ID if one can be had. North American Indian Artifacts
looks to be! looks to me like a scraper? definitly has been worked because you can see the flaking... keep looking in that area! the natives traveled by rivers and streams so makes sence you found it by a creek, I am no expert so correct me if I am wrong! also you might want to check out All Arrowhead Types and Ancient Indian Artifacts - Arrowheads.com they can tell you ALOT! iv posted a few things on there and right away they tell me the material and somtimes age and definitly what it was used for!