The elevation of the streets hereinafter mentioned shall be fixed and established with reference to and shall conform to the City bench mark, which is a copper monument in the southwest corner of the cement floor of the vestibule of the public school of Grace, Idaho, which bench mark was established by the U.S. Geological Survey, and is so marked and the elevation of which is 5535.965 feet above sea level according to the official records of the United States Geological Survey. (Ord. 20, 5-8-17)