This is an enlarged front (left) and back of the Kinderhook plate now owned by the Chicago Historical Society. Actual size of the bell-shaped plate is 2 7/8" high by 2 1/4" wide at the bottom, tapering to 1 3/16" at the top; average thickness is 1/32". The nickel-size splotch on the backside is likely due to corrosion since its 1843 "discovery." Photographs courtesy Chicago Historical Society.