Covered with SiO2 and CaO3. Two upright spikes on one side, one on each half of shoe; three bent spikes on each half of same side. "This Horseshoe was coated with SiO2 and CaO3 in Geyser pool. It was placed there by Emmett Carpenter, Supt. of Yellowstone Park. M. F. Arey" found on paper with horseshoe.