The area and dimension provisions of the sections dealing with property development standards shall apply to all lots; provided, however, that where a lot has a width or area less than that required in the zoning district of which it is a part, and was held under separate ownership or was of record at the time the ordinance codified in this title became effective, such lot may be occupied by the uses permitted in the district, subject to the area per dwelling unit and yard requirements, and such other regulations as apply uniformly to all lots in that district. (Ord. 1000 § 5, 1955)