Photos 4 & 5: Obverse and reverse photos of the Northumberland Fluted knife
form. Cherts are jasper, black chert, black/brown chert. Number one in the bottom row is a cast of the largest
known example found in western Pennsylvania. Number six in the bottom row is a personal find of the author. Number
six in the top row was found in Northumberland County, Pennsylvania, for which the type was named.