Out-of-place artifact

Link - Permalink

An out-of-place artifact (OOPArt) is a term coined by American zoologist and cryptozoologist Ivan T. Sanderson for an object of historical, archaeological or paleontological interest found in a very unusual or seemingly impossible context.

An example of an OOPArt is the Maine penny, found at the Goddard site in Blue Hill, Maine. It is an 11th century Norse coin which was found in an American Indian shell midden. Over 20,000 objects were found over a 15-year period at the site. The sole non-Native artifact was the coin.

Source