Within the districts established by Title Three of this Ordinance, or amendments hereinafter adopted, there may exist lots, structures, uses of land and structure which were lawful before this Ordinance was passed or amended, but which would be prohibited, regulated or restricted under the terms of this Ordinance or future amendments. It is the intent of this Ordinance to permit such nonconformities to continue until they are removed and to allow reasonable expansion, but not to encourage their survival.