FREDERICKTOWN, MO., October 22, 1861.

CAPTAIN: I beg leave to submit the following remarks supplementary to my report upon the engagement yesterday:

The embarrassing relations existing between Colonel Plummer and myself respecting the command induced me to confine my report to the operations of my own troops from Pilot Knob, leaving Colonel Plummer to do justice to his troops. Being senior by commission to Colonel Plummer, I claimed the command, but Colonel Ross, Seventeenth Illinois Volunteers, senior to both, had decided to claim command if Colonel Plummer had been superseded by me. To avoid the vast injury to our cause resulting from such a dispute, it, was arranged between Colonel Plummer and myself that one of us should hold this place, with a force sufficient to protect the wounded and to keep communication with Pilot Knob, as well as a support for the main force if it had to fall back. In deference to the greater experience of Colonel Plummer I chose to remain here, and detached from my command the Twenty-first and Thirty-third Illinois Volunteers, five companies First Indiana Cavalry, and Schofield's artillery, to accompany him in pursuit of the rebels. My own regiment, three companies of cavalry, and two 24-pounder howitzers constitute the force at this place.

In a note to you on the 21st I informed you that the enemy had left for Greenville, but a few hours afterwards the cannonading on the Greenville road notified me that they had moved to a new position, where they were met by Colonel Plummer's advance guard, which had just taken up its march in pursuit of the enemy. The battle was entirely unexpected by Colonel Plummer as well as myself.

Very respectfully, your obedient servant,

W. P. CARLIN,

Colonel Thirty-eight Illinois Volunteers.

Captain C. McKEEVER,

A. A. G., Western Department, Saint Louis, Mo.

HEADQUARTERS,
Pilot Knob, Mo., October 25, 1861.

CAPTAIN: I have the honor to report my return to this place with the last of my force from Fredericktown, excepting Captain Hawkins' cavalry company, which I left there to procure transportation for a few sick men and to bring them in. In my last reported I informed you that I had detached the Twenty-first and Thirty-third Illinois Volunteers, the First Indiana Cavalry, and Schofield's artillery, to accompany Colonel Plummer in pursuit of Thompson. After one day's march the colonel decided to discontinue the pursuit, and returned on the 23rd to Fredericktown. On the 24th I sent the same force above mentioned into this place, remaining at Fredericktown with my regiment, two companies of cavalry, and two 24-pounder howitzers, all of which I brought in to-day with the exception mentioned.

The prisoners not wounded were delivered to Colonel Plummer, who took them to Cape Girardeau to work on the fortifications. The wounded prisoners I left at Fredericktown in the hands of competent physicians, and well provided for generally. They are under oath to deliver themselves to me on recovery. There are 34 sick and wounded prisoners, and near 40 with Colonel Plummer. During the 22nd, 23rd, and 24th we were burying the dead and bringing in the wounded of the enemy. The longer we remained the nearer we could approach to accurate estimate