(A) The datum for the establishment of grades in the city is hereby established as a horizontal plane.
(1) 134.58 feet below an X on the top of the stone water table of the City Hall of the city at the southeast corner of said City Hall;
(2) 128.58 feet below an X on the east pedestal base of the southeast corner entrance of the three-story brick building located on the east half of Lot 335, Lake Forest, Illinois;
(3) 123.66 feet below an X on the top of water table of the brick corner post at the southeast corner of the building located on the southeast corner of Lot 342, Lake Forest, Illinois;
(4) 106.87 feet below an X on the northwest corner of the top stone step of the west entrance to the Edward F. Gorton School Building located at the northeasterly corner of McKinley Road and Illinois Avenue, Lake Forest, Illinois;
(5) 91.2 feet below an X on the northwesterly corner of the Henry C. Durand Art Institute building located on Lot 106, Lake Forest, Illinois; and
(6) 132.506 feet below the top of a United States Geological Survey bench mark stamped “Principal Traverse Station 12,1906,” located in the southeast corner of the City Hall fawn, 33 feet north of the center line of Deerpath and 31 feet west of the center line of Forest Avenue U.S.G.S. bench mark elevation 712.676.
(B) All grades now and hereafter fixed shall have reference to the base or datum plan herein established.
(Prior Code, § 2-179)