I dont know rock but I dont think its a guilford, they seem like longer narrower points but it could be. I dont know of many of those being found in this area.I guess its hard to tell by looking at the pictures, I wish I had a better camera. That would be cool to know one eas a beaver lake though. I have heard of those being found around here.I appreciate everyones opinion on it though, and I hope you find that killer piece you are looking for on your next hunt.