Strike Doubling Caused Liberty's Gown to Shown on the Rim

This Presidential Dollar reverse shows "strike doubling," also called "mechanical doubling." The Statue of Liberty's gown appears on the rim of the coin because the dies actually bounced a little following the strike. Error coin purists consider such coins to be "damaged," but the average collector finds them to be pretty neat! They're not worth much, perhaps $10 or so on eBay. They are known for all Presidential Dollars released so far, although the example shown is a Washington Dollar.