1999 Proof Yellowstone National Park Silver Dollar This 1999 P Yellowstone National Park Proof Silver Dollar was minted in Philadelphia. The coin weighs 26.73 grams and has a diameter of 1.5 inches. Obverse: A Geyser erupting at Yellowstone; Reverse: Buffalo from the Interior Department's Seal. Edgar Steever designed the obverse; William Cousins designed the reverse. This coin comes with a Treasury Certificate of Authenticity.