In addition to the regulations for development and use of the site imposed by the basic zone district, use, alterations, new construction, relocations, demolitions, and excavations which affect historic structures, objects, sites or districts in the Historic Landmark “L” Combining District shall be subject to the regulations set forth in the County Code, Chapter 16.42, Historic Resource Preservation. (Ord. 2493, 10/18/77; 3344, 11/23/82; 3432, 8/23/83; 3632, 3/26/85; 3927, 6/28/88)