This title shall consist of the text hereof, as well as that certain map identified by the approving signatures of the City Council, marked and designated as "Map of the Zoning Act", which said map is now on file in the Office of the Clerk. Said map has been heretofore examined in detail by the City Council and is hereby adopted as a part of this title, but this title and said map shall be subject to change from time to time as may be determined by the City Council by amendment of this title. (Ord. 19, 12-5-1973)