Hall City Cave, a limestone cave system near Hayfork in northern California, is notable for both its geology and the traditions attached to it. Documented exploration in 1903 produced a Permian-age ammonite fossil, and the cave’s deep water-filled shaft became a focus of lasting curiosity. For the Nor-el-muk and other Wintu Native Americans, it was a sacred place, remembered in accounts by a Wintu woman named Lucy later recorded by Edith Van Allen Murphy. The cave is also linked to a persistent but unconfirmed legend of forty thousand dollars in gold supposedly lost in the flooded shaft, a story that continued to inspire exploration, including a 2012 OpenROV survey.