The lawful use of any land existing at the time of the adoption of this chapter may be continued, although such use does not conform with the provisions of this chapter except as hereinafter provided.
No building permit shall be issued and no nonconforming use shall hereafter be extended or enlarged except following authorization by the Board of Appeals as a special extension. Any nonconforming use which lies abandoned or discontinued for a period of 12 consecutive months shall not be permitted to be reestablished as a nonconforming use.