noun: (historical) The belief, held mostly in the 18th century, that rocks were formed in fire. It was a rival theory to Neptunism.
noun: Alternative spelling of Vulcanism (“historical scientific view”) [(historical) The belief, held mostly in the 18th century, that rocks were formed in fire. It was a rival theory to Neptunism.]
noun: Alternative spelling of volcanism (“volcanic activity”) [(volcanology) Any of the natural phenomena and processes associated with the action of volcanos, geysers and fumaroles]
