Laws of 1887 authorized the Adjutant General "to procure copies of all military records relating to New York volunteers in the war of the rebellion, not on file in his office, from the proper departments of the general government." In addition, the Adjutant General was "to establish as part of his office a bureau of records of the war of the rebellion, in which all records in his office relating to said war, and the records and relics of the bureau of military statistics shall be united and kept."
Although the exact collation date of these records is unknown, they were probably produced during the same period when the abstracts for men who served in New York Volunteer units, the United States Navy and Marine Corps, or State Militia were being compiled. According to annual reports submitted by the chief of the Bureau of Records of the War of the Rebellion to the Adjutant General, this was between 1887 and 1907.
From the description of Abstracts of muster rolls for colored enlisted men unassigned to any unit during the Civil War, 1863-1865. (New York State Archives). WorldCat record id: 84965001
