Numbers 5. Report of Captain Thomas Logan, Twelfth Illinois Cavalry.

Williamsport, Md., October 15, 1862.

COLONEL: In accordance with an order received from your head quarters delivered me at 5.30 p. m. on the 7th instant, ordering my command to report to Captain Gary, at Clear Spring, to assist in picketing the Potomac River from McCoy's Ferry to Cherry Run I proceeded, leaving Williamsport, Md., at 6 p. m. same day, arriving at Clear Spring at 8 o'clock. Report to Captain Gary and proceeded to the Four Locks, where I found Captain Treichel, in command of two companies of the Third Pennsylvania Cavalry. I encamped here for the night, positing a picket on the Cherry Run road, at Green Spring Furnace.

Next morning, I moved my command to a cross-road half a mile east of Green Spring Furnace, and about 1 mile from McCoy's Ferry. I agreed with Captain Treichel to picket the Cherry Run road, from Green Spring Furnace to Cherry Run, a distance for 3 1/2 miles, and also to picket the draw-bridge the canal, immediately south of old Fort Frederick.

On the morning of the 8th I placed my pickets accordingly, placing 4 men at the furnace, where the Cherry Run road crosses the road from the mountain to McCoy's Ferry, and only about a half mile from the ferry; 4 men at the bridge before mentioned; 4 men on the hill at the school house 2 miles from Cherry Run, and 4 men to patrol the road from this point to the ferry or ford, called Charry Run. My pickets remained as above posted during the days and nights of the 8th and 9th instant nothing occurring worth notice.

On the morning of the 10th, at daybreak, by my time 5.30 a. m. i was informed by Mr. Jacques, a citizen living near my reserve, that the enemy were crossing at McCoy's Ferry, apparently in force. I immediately ordered my reserve to mount, starting a messenger at the same time to Captain Garry, at Clear Spring, and getting my camp equipage and baggage loaded. I started the team to Clear Spring, and was drawn up in line of battle in five minutes. Knowing that the crossing at McCoy's Ferry, being below all my pickets, would cut them off, I ordered Sergt. E. N. Pratt to proceed with 3 men, and, if possible pass the cross road at the furnace before the enemy occupied the place, gather up all my pickets, and go to Fairview and down the pike to Clear Spring which he succeeded in doing, not, however, until 3 p. m. having been cut off, and, at one time, surrounded by the enemy. I feel that Sergeant Pratt and the 16 men with him deserve great praise for their courage and discretion.

At about 5.40 o'clock the enemy fired ten or fifteen shots on my pickets falling back on the reserve in good order. The enemy immediately occupied the crossroads and planted one gun on the hill opposite the furnace, near the store, commanding the cross-roads and the road up to my reserve. On seeing artillery I immediately dispatched a second messenger with these facts to Captain Gary. The messenger found, on arriving at Clear Spring, that Captain Gary had fallen back to Dam No. 5, where he proceeded to report. By this messenger, on his return messenger, on his return, I was ordered to fall back by Four Locks to Dam Numbers 5. Before receiving this order, which was not received until 9 a. m., owing to the distance, I had (believing the force intended to proceed immediately to Clear Spring) fallen back on the Clear Spring road one-half or three-fourths of a mile,