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.