Castle, one of the few predictable geysers in Yellowstone, is located in the Upper Geyser Basin, a short walk from its more famous relative, Old Faithful. Its cone, made of siliceous sinter, or geyserite, builds at the rate of about half an inch to one inch per century. Castle is one of the world’s oldest active geysers.
NOTE: The preceding description for the “Castle Geyser” lithographic note card appears on the reverse of this card.
Full-size prints are also available here here.