Subject to the provisions of this article, a nonconforming lot, nonconforming structure or nonconforming use may be continued even though such does not conform with the provisions of these regulations for the district in which it is located. The Zoning Officer may keep and maintain a list of all nonconforming lots, structures or uses existing at the time of the passage of this chapter, its predecessors or amendments thereto, and which may come to exist in the future.