If the other side is beveled ? it's a Lost Lake, Decatur, or Plevna ( also called Dovetail), all part of the Kirk family. Made from sky blue Ft. Payne chert, hence the brown patina with the white lines. Yours is a typical clean break fracture, side to side, instead of an impact fracture. Producing a flute like scar. In my opinion, you have the mid-section of a old broken worn out knife. Late early to mid Archaic. South Middle Tennessee to North Middle Alabama for the chert source.