Four (4) stories, not to exceed sixty-five (65) feet maximum, but not applicable to church spires, belfries, cupolas, chimneys, radio and flag poles and gas holders, which shall not exceed thirty-three (33) percent of the floor area of the first floor, and provided that such church spires, belfries, cupolas, chimneys, radio and flag poles and gas holders shall not be more than fifty (50) percent higher than the average height of the roof of the main structure.