The card you note appears to be a rather cryptic endorsement which I would assume refers to Col. Poindexter and based on the card noted above, "Gen. Merrill's order/s."
The last card in the file I see, which is torn up, is headed Boone County, then "Merrills order, released, Alton with Poindexter [lined through and replaced by] Porter, now at Gratiot" Many other line outs and rather disjointed.