What is a silver coin with a ladies head on one side and an eagle on the other?

An eagle is on the back of all true silver dollars (1794-1935) as well as cupro-nickel Eisenhower (1971-78) and Susan B. Anthony (1979-81, 1999), and brass Sacajawea (2000-2008) dollars.

Presidential dollars have the Statue of Liberty on the back. New Sacajawea dollars have a different Native American design every year.