D Over S

One major variety is the 1950 D/S Washington Quarter. This coin features a Denver "D" mintmark struck and punched over a San Francisco "S" mint mark (OMM variety). The best way to identify this coin is to note that parts of the underlying "S" are seen near the upper/upper-left portion of the "D". The "D" appears slightly doubled just to the right of the "D" mintmark.