The William A. Revell Note consists of a single envelope on which Revell has written a note referring to passages in J. C. Hadley's Memorial of Henry Sanford Gansevoort (1882). Written on both sides of a small envelope, Revell's note describes the wounding and capture of Confederate ranger Colonel John Singleton Mosby, at which Revell had been present as an officer in the 13th New York Cavalry. Specifically, Revell writes of his role in Mosby's capture and of the fates of Mosby's cloak and boots.