The spot "twenty miles ahead" of the Tallahatchie Crossing, where Lieutenant Backhouse has led his troop "trying to find something to lead another charge against" (692). He is placed under arrest here by General Forrest's provost.
In "My Grandmother Millard" this is the spot "twenty miles ahead" (i.e. further north) of the Tallahatchie Crossing, to which Lieutenant Backhouse leads his troop in defiance of his orders (692). He is placed under arrest here by General Forrest's provost.
The "provost" who arrests Philip for disobeying orders (692). In the Confederate armies, provosts were charged with maintaining discipline - like military police in the modern U.S. armed forces. (The second time the story refers to him, "Provost" is capitalized, 694.)