The following is a full abstract of the Official Report of Captain James St. Glair Morton, Corps of Engineers, commanding Brigade of Pioneers:
The Pioneer Brigade of the Army of the Cumberland consists of three battalions of infantry, selected from forty different regiments, and the Chicago Board of Trade Battery, Captain Stokes. Captain Bridges, of the Nineteenth Illinois, commanded the First Battalion; Captain Hood, of the Eleventh Michigan, the Second, and Captain Clements, of the Sixty-Ninth Ohio, the Third Battalion.
Sources: Official Roster of the Soldiers of the State of Ohio Name: Robert Clements Age at enlistment: 28 Birth Date: abt 1833 Enlistment Date: 10 Sep 1861 Rank at enlistment: Captain State Served: Ohio Service Record: Commissioned an officer in Company F, Ohio 69th Infantry Regiment on 31 Dec 1861.
According to Headstones Provided for Deceased Union Civil War Veterans Robert Clements,Captain of Company "F" 69th Ohio Infantry is buried at Greenwood Cemetery at Hamilton, Ohio. He died October 29. 1870.
You might want to call them, they may be able email you a photo of the marker.