The following is taken from New York in the War of the Rebellion, 3rd ed. Frederick Phisterer. Albany: J. B. Lyon Company, 1912.
By special order of the War Department, dated June 23, 1865, the 13th [Regiment] and 16th Regiments of Cavalry were consolidated, and the consolidated force designated as above. The consolidation took place August 17, 1865, as follows: Company A was formed of F of the 13th, and G of the 16th Cavalry; B of G 13th, and F 16th; C of L 13th, and B 16th; d of D 13th, and E 16th; E of I 13th and 16; F of H 13th, and L 16th; G of A 13th, and M 16th; H of C 13th, and A 16th; I of M 13th, and C 16th; K of K 13th and D 16th; L of E 13th, and H 16th; and M of B 13th and K 16th Cavalry, and Col. Nelson B. Sweitzer, 16th Cavalry, was placed in command of the new organization, which was honorably discharged and mustered out under his command, September 21, 1865, at Camp Barry near Washington, D. C., having lost by death of disease and other causes, four enlisted men.

The following is taken from The Union army: a history of military affairs in the loyal states, 1861-65 -- records of the regiments in the Union army -- cyclopedia of battles -- memoirs of commanders and soldiers. Madison, WI: Federal Pub. Co., 1908.
Third Provisional Cavalry.—Col., Nelson B. Sweitzer; Lieut.-Col., Nathaniel Coles; Majs., George B. Bosworth, John Birdsall, Charles H. Hatch. This regiment was formed by the consolidation of the 13th and 16th regiments of cavalry on June 23, 1865. Col. Sweitzer was given the command of the new organization, which was mustered out of service on Sept. 21, 1865, at Camp Barry, near Washington, D. C. Its loss from disease and other causes was 4 enlisted men.