Late in the evening of the same day, I crossed the river, assumed command, and disposed my force for defense . During the night, our force was increased by our companies from Columbia (three white and one colored), numbering about 175 men, Very early next morning, having obtained entrenching tools from citizens of Columbia and the Pennsylvania railroad, my own men and the negro company (the order three companies from Columbia having left for their homes) dug rifle-pits on their side of the turnpike . During the morning, a detachment of convalescent soldiers from York, and the Patapsco Guards, in all about 250 men, joined me, and they were posted on the left of the town, m protecting the flank left of my position . They were placed under command of Lieutenant-Colonel Green . We were also joined scattered fragments of the twentieth regiment Pennsylvania Volunteer Militia, under Lieutenant-Colonel Sickles, during the morning, which I posted on the right of the own as a protection to the right flank. The work of entrenching was continued until the approach and attack of the enemy, about 5. 30 p. m., and, while the work was in progress, I selected, with the assistance of Major Haller, aide-de-camp to the commanding general, the several points at which to post my limited number of men . The main body of the enemy, about 2, 500 strong, composed of cavalry, artillery, and infantry, took up their position about 6 p. m. on the turnpike in our immediate front within three-quarters of a mile of our rifle-pits. A force of cavalry and infantry moved down the railroad on our left, and attacked, our skirmishers, who after replying to their fire for a short time, retired to the main body, which kept up a steady fire, and held the enemy in check until they received orders to retire to the brigade . The rebels succeeded in getting a battery in position on the elevated ground on our right and a section in our immediate front. These guns were used most vigorously against those of my command occupying the rifle-pits. In the meantime, they sent a column of infantry, under cover of a high hill on our right, within a few hundred yards of the river . none but their skirmishers approached within range of the guns of the men occupying the rifle -pit, and these being in a grain, and obscured from our view, excepting when they would rise to fire, it was difficult to do them much harm or dislodge them, . They depended exclusively upon their artillery to drive us from our position here. having no artillery ourselves on that side of the river with which to reply, and after retaining our position for about one and a quarter hours, and discovering that our remaining longer would enable the enemy to reach the river on both of my flanks, which I was unable to prevent because of the small number of men under my command, and thus get possession of the bridge, cut off our retreat, and secure a crossing of the Susquehanna, which I was instructed to prevent, I retired in good order, and crossed the bridge to the Lancaster side . Before the enemy had left York for the river here, I made, as I supposed, every necessary arrangement to blow up one span of the Columbia Bridge . When they got within sight, the gentlemen charged with the execution of that work repaired promptly to the bridge, and commenced sawing off the arches and heavy timbers preparatory to blowing it up powder, which they had arranged for that purpose . After an abundance of time was allowed, and after I supposed every man of my command was over the river, when the enemy had