The Northeast corner of the lower stone water table at the Northeast corner of the two story brick building known as Itasca Village Hall on the west side of Walnut Street in the village, which is 688.35 feet above sea level datum, is hereby fixed and established as the datum base line or village standard bench from which all grades or elevations for public uses, public works or public improvements of the village shall refer or be deduced.
('52 Code, Ch. 8, § 115)