a. On and after July first, nineteen hundred sixty-four, the use of the land maps in the offices of the city register and in the offices of the clerks of the counties of New York, Bronx, Kings and Queens, shall be discontinued, and on and after July first, nineteen hundred sixty-four, reference shall be had to the tax maps for the boroughs of Manhattan, Bronx, Brooklyn and Queens and to block numbers designated thereon for the purpose of indexing, recording or filing of instruments affecting title or relating to real property in such counties and the tax maps for said boroughs shall be conclusive as to the location of block boundaries and block numbers. The tax map for each borough may be referred to as the land map for the particular county which it affects.
b. Whenever any block boundaries shall be changed or any new or additional blocks of land shall be formed in such counties by the opening or closing of any street, avenue, road, boulevard or parkway or otherwise, the department of finance shall cause such maps to be altered to show the changes in the boundaries of a block and the formation of such new or additional blocks, and to cause such blocks, the boundaries of which have been altered, and such new or additional blocks, to be numbered on such maps with such block numbers as such department may determine. The commissioner of finance, or an officer or employee of the department designated by the commissioner, shall certify and file annually with the register and county clerk in each of such counties a list of the numbers of the blocks, the boundaries of which have been altered, and a list of the numbers of new or additional blocks which have been formed.
c. For the purpose of notice under any of the provisions of law for the recording of instruments affecting or relating to land in such counties, each block shall be deemed to extend to the middle lines of the streets, avenue, roads and boulevards laid out on such land maps fronting and adjoining such block, and shall also be deemed to extend to the exterior bulkhead line or to the exterior line of grants of land under water where water forms one of the boundaries of a block.
d. The word "block", as used in this section designates a plot or parcel of land such as is commonly so designated in the city, wholly embraced within the continuous lines of streets, or streets and waterfront taken together where water forms one of the boundaries of a block, and such other parcels of land or land under water as may be indicated by the department of finance upon such tax maps by block numbers as constituting blocks.