Terry,
I looked thru the file that I have on JJ Calkins, in a Widow Declaration of Pension, she writes that Calkins had served for "nearly one year as Landsman and Fleet Paymasters Clerk" and in a book titled "The Calkins Memorial Military Roster" written by William Wirt Calkins in 1903, J.J. Calkins has a short entry that gives his war service. "Lieut.Calkins first entered the service in the Navy, shipping on the Steamer Michigan at Erie, PA. as Landsman, Oct.31, '62. Was discharged Dec. 17, '62 and appointed Clerk to Fleet Paymaster, E.W. Dunn, "Miss. Flotilla." He served as such until Nov. 4, 1863, when he resigned, and on Jan. 26, 1864, was commissioned Second Lieutenant in Battery C, 1rst Mich. Lt. Art.
I do not have Calkin's Military records from the Archives.