The following troops of the Army of the Potomac were left behind or detached on and in front of the Potomac for the defense of that line April 1, 1862. ....
GENERAL WADSWORTH'S COMMAND
[I didn't transcribe the cavalry.]
Artillery and Infantry.--
[I transcribed only the 91st]
Ninety-First Pennsylvania Volunteers, Franklin Square Barracks;
[Official Records series 1 volume 5 pages 21-22]