The base on this Allen County, Indiana, Thebes snapped in Early Archaic usage, it was salvaged as there was still considerable cutting blade remaining. Across the base you really feel the polish to that broken basal edge. Starting with a 10 loop, followed by a 30x and finally a 60x magnification I find no grinder marks, I have to conclude the piece is entirely ancient salvage. Too, there is mineralization on the base, what you'd expect from an ancient salvage job. The notches on this piece are so wide it's close enough to call an "E -notch"--I'll display it next to another E-notch in my Thebes case. Length is 3&1/4", width is 1&7/16", 5/16" max thickness. That tip, you can see the quartz inclusion in the Coshocton--neat feature. The blade edges show some absolutely great pressure flaking & patina. Guarantee: to the best of my experience the piece is 100% authentic, and if you're not satisfied with it, send it back. Because the base is so unusual I cannot predict what each and every working authenticator might say (about the basal edge), but I think it's real--it'll always have a home in my personal collection. Enough said. Shipping is $6.00, checks or M.O.s are welcomed--I do not use paypal--Roy A.