Out of western Kentucky, somewhere in the Owensboro, KY, area was about all the provenance the last owner collected on this (and a second) blade--more finished-out than a Cache Blade, thinner, too. Length is 3.75" by 2.13"--caliper goes slightly over 3/8" max thickness near the base. If the title was a 'Now what's he mean by that?"--calcium adhesions--mussel shells deteriorating, the calcium leaching onto the hornstone (Harrison County, Indiana Hornstone). Sometimes (in the garbage pile) you'd have rotting bones that also 'leach' calcium onto flint, whatever is "in situ". One spot on the base of this blade has what looks like the white bit of mussel shell. Culture: in the Mid-to-Late Archaic periods campsites, Riverton Peoples, would build up a shell mound along area rivers. If you toss enough garbage on a riverbank, eventually you get more than a "Midden", you get a Shell Main. Why usable flint blades would be in the debris I can't answer--in this case there'd even been a small finishing notch on the blade edge--call it a shaft scraper for lack of a better explanation. One note--on the rounded tip there is a bit of work polish--you'll feel it. Was this an 'opener' for mussel shells? That's my guess. Every detail is guaranteed authentic. Shipping is $6.00, checks or M.O>s welcomed. Sorry, I do not use paypal--Roy A.