Within the zoning districts established by this title, or zoning district amendments that may later be adopted, there may exist uses that were legally established prior to the effective date of this title, or applicable amendment, that are classified as a Class 1, II or III use in a particular zoning district. Such uses shall be considered Existing Class 1, II or III uses, and subject to the review standards pertaining thereto. (Ord. 1634, § 21, 2004.)