Hey Clark nice find in the creek
It's obviously been partially and purposefully ground and pecked in order to be hafted to a handle
The earliest datable pecking and grinding processes used by Indians begin in the middle Archaic period (approximately 4-5,000 BC), so it's definitely not Paleolithic. "Crudely made" hammerstones and axes is not an indication of age. It could have been made any time during the mid-archaic to the historic period. The term Neolithic is not usually used by archaeologists to point to a particular time period because it can denote vastly different time periods depending on the context of it's usage, rather it is used to describe a new stone tool technology taking place. The term actually just means a time of new stone technology.