Please answer the following question: Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Sulphur Springs Mountain -  Sulphur Springs Mountain (or Sulfur Springs Mountain) is a mountain in southwestern Solano County California. The slopes can be accessed via hiking trails emanating from Blue Rock Springs Park in the city of Vallejo. Cinnabar deposits were extracted from this location in the early 1900s at Hastings Mine and St. John's Mine. Both mines are classified as medium priority mine from the standpoint of environmental oversight for California inactive mines.
Answer:
Natural Place