N.Y. RPP Law § 315

§ 315. Recording books. Different sets of books must be provided by\nthe recording officer of each county, for the recording of deeds and\nmortgages; in one of which sets he must record all conveyances and other\ninstruments absolute in their terms, which are not intended as mortgages\nor securities in the nature of mortgages, and all executory contracts\nfor the sale, purchase or exchange of real property, or memoranda\nthereof, and all instruments canceling or extending such contracts,\nwhich conveyances, contracts or instruments are delivered to him,\npursuant to law, to be so recorded, and all forms pertaining to\ncommitments of land to continued agricultural production required to be\nso recorded pursuant to section three hundred six of the agriculture and\nmarkets law; and in the other set, such mortgages and securities, and\nassignments of rent, delivered to him; excepting that if the recording\nis by microphotography or other photographic process, the recording\nofficer shall not be required to maintain books for such records, but\nshall provide such filing equipment as he may deem appropriate. The\nrecording officer may, in his discretion, record in consecutive order\nthe instruments received by him, and shall not be required to segregate\nmortgages from deeds or other classes of instruments.\n