1979-s Type 2 Washington Quarter 25c Graded pr70 dcam By SEGS. In 1979 the U.S. Mint struck Proof Washington Quarters with two different mint marks. The first or Type 1 mint mark looks filled or not as clear, so it is referred to as the filled s mint mark. The Type 2 mint mark is much clearer, therefore, it is refrred to as the clear S mint mark. Both mint marks are easy to dustinguish.