Thats actually plate or plate shift doubling. It is caused when the thin copper plating on the planchet shifts during the squeezing of the coin. It is fairly common. In extreme cases the shift is accompanied by a split through which the zinc may be seen, Richard
Actually, Ziggy has it right. This coin exhibits plate shift doubling. the type of doubling that JC is trying to explain is the result of the strike actually breaking through the plating right next to and around the letters or devices on a coin. That is called plate split doubling and is damage. Thanks, Bill PS: There may be some plate split doubling effecting the D mintmark but the date is plate shift doubling
