I don't know what you would call this but it sure looks like an extra left hind leg or some type of same impression. Can anyone tell me what this is? Thanks. http://home.comcast.net/~skipa97/2005bison.htm
Perhaps a clash mark? That would depend if there's a straight edge in the obverse design that corresponds in size, shape, and position to the defect on the reverse. It could also be a shallow die dent that coincidentally matches the shape of the leg. Or it could be a counterclash error. This occurs when a die strikes a piece of scrap metal, and the metal is struck again, transferring the design back to the die face. Subsequent coins show the results of that impact in the form of raised, normally-oriented, oddly positioned extra design elements.
