To cover the flanks in the forest Dudley deployed as skirmishers the 8th New Hampshire on the right, and on the left the 3d and the 31st Massachusetts, supported by the 2d Illinois. Robinson was with the cavalry train, which was rather closely following the march of its division, in order to clear the head of the infantry without starving the cavalry.
Neither side could move forward without bringing on a battle. But Lee, instead of being able and ready to disengage his cavalry advance-guard and to fall back to a chosen field, was now anchored to the ground where he found himself, not alone by the concentration of the main body of the cavalry at the very front, but also and even more firmly by the presence of the infantry with its artillery and their employment, naturally enough, to form the centre of his main line.
The clearing, the largest yet seen by the Union Army since entering the interminable wilderness of pines, was barely half a mile in width; across the road it stretched for about three quarters of a mile, and down the middle it was divided by a ravine.
Directly in front of Banks stood Taylor in order of battle, covering the crossing of the ways that lead to Pleasant Hill, to Shreveport, to Bayou Pierre, and to the Sabine. On his right was the cavalry of Bee, then Walker's infantry astride of the main road, and on Walker's left Mouton, supported on his left by the cavalry brigades of Major and Bagby, dismounted. To this position, well selected, Taylor had advanced from Mansfield early in the morning, with the clear intention of offering battle, and, regardless of Kirby Smith's purpose of concentrating nearer Shreveport, had sent back orders for Churchill and Parsons to come forward. They marched early, and were by this time well on the way, but a distance of twenty-five miles separated their camp of the night before from the field of the approaching combat.
As on the previous day's march, Stone had been with Lee's advance since the early morning, without, however, being charged with the views of his chief and without attempting to issue orders in his name; but now Banks himself rode to the extreme front, as his habit was. Arriving on the ground not long after Ransom, and seeing the enemy before him in force, Banks at once ordered Lee to hold his ground and sent back orders to Franklin to bring forward the column. The skirmishing that had been going on all the morning, as an incident of the advance and retreat of the opposing forces, had become the sharp prelude of battle, and through the openings of the forest the enemy could be seen in continuous movement toward his left. This was Major and Mouton feeling their way to the Union right, beyond which and diagonally across the front ran the road that leads from Mansfield to Bayou Pierre.
Whether Taylor, as he says, now became impatient at the delay and ordered Mouton to open the attack, or whether, as others have asserted, Mouton attacked without the knowledge or orders of Taylor, is not quite clear, nor is it here material. About four o'clock, when the two lines had looked at each other for two hours or more, Taylor suddenly delivered his attack by a vigorous charge of Mouton's division on the east of the road. Ransom's infantry on the field numbered about 2,400 officers and men; including Lucas, Banks's fighting line fell below 3,500, and the whole force he had at hand was not above 5,000 strong. Against this, Taylor was now advancing with nearly 10,000. It was therefore inevitable that on both flanks his line must widely overlap that of Banks as soon as the two should meet.
When Ransom perceived Mouton's movement, he threw forward his right to meet it with such spirit that Mouton's first line was driven back in confusion on his second; then rallying and returning to the charge, Mouton's men halted, lay down, and began firing at about two hundred yards' range. The two batteries of Landram's division, Cone's Chicago Mercantile, and Klauss's 1st Indiana, now came on the field, and were posted by Ransom on the ridge near the centre, to oppose the enemy's advance on the left, before which Dudley's men were already falling back. Bee and Walker had in fact turned the whole left flank, and were rapidly moving on, breaking in the line as they advanced. This soon left Nims's guns without support, and at the same time Klauss and Cone came under a fire so severe from Walker's men, that Ransom determined to withdraw to the cover of the wood in his rear at the edge of the clearing. Unfortunately, Captain Dickey, his assistant adjutant-general, fell mortally wounded in the act of communicating these orders, and thus some of the regiments farther toward the right, being without orders, and fighting stubbornly against great odds, stood their ground until they were completely surrounded and taken prisoners. While aiding Landram to rally and reform the remnants of his division in the skirt of timber, Ransom was severely wounded in the knee, and had to be carried off the field. Vance and Emerson were wounded and taken prisoners, each at the head of his brigade.
Meanwhile, shortly after three o'clock, at his quarters, near Ransom's camp of the forenoon, Franklin received his first suggestion of an impending battle, in Banks's order to bring all the infantry to the front. First sending back word to Emory, Franklin set out at once and rode forward rapidly, followed by Cameron's division. When, some time after four o'clock, he entered the clearing and galloped to the hill where the guns of Nims still stood grimly defiant and Ransom's men were still desperately struggling to hold their first ground, the situation was already hopeless. Hardly had he arrived on the ground, than, by a single volley from Walker's advancing lines, Franklin's horse was killed, and he himself and Captains Chapman and Pigman of his staff were wounded.
Cameron came up just as Landram was striving hard to rally his men and to hold a second position in the lower skirt of the wood, to prevent the enemy from coming on across the clearing; but for this, time and numbers and elbow-room were alike wanting. Moreover, every movement of the Confederate troopers must be gaining on the flanks. Nor was Cameron's handful, barely 1,300, enough to enable the remnant of the Thirteenth Corps to hold for many minutes so weak a position against such odds. Cameron deployed his four battalions and tried hard, but the whole line soon crumbled and fell apart to the rear.
Until this moment, Banks and Franklin, as well as every officer of the staff of either, beginning with Stone, had exerted themselves to the utmost to second the efforts of Ransom and of Landram to save the day. The retreat once fairly began, all attempt to stay its course was for a time given up as idle, for every man knew just how far back he must go to find room to form a line of battle longer than the road was narrow. Green's cavalry having been for the most part dismounted and on the flanks, as well as in the forest, the pursuit was not very vigorous and was now and then retarded by the successive covering lines of Lucas and of Dudley, so that the prospect seemed fair of bringing off the remnants of the fighting force without much more loss, when about a mile behind the battle-field, at the foot of a slight descent, the retreating column came upon a knot of wagons inextricably tangled and stuck fast in a slough. This was the great cavalry train trying to escape. Instantly what had been a severe check became a serious disaster. Already, by holding so stiffly to his first position, in the front line, in the road, Nims had lost more than half his horses, and thus in quitting the field he found himself compelled to abandon three of his guns; yet not until he had inflicted vast injuries on his enemy, and to the last furnished a noble example of coolness in the performance of duty and the highest courage in the hour of trial. Now the remnant of this fine battery was swallowed up in the wreck of the wagons, and soon fourteen more guns went to swell the ruin. Thus Rails and Rottaken lost each a section, Cone and Klauss their whole batteries. In all twenty guns were lost; three on the field and seventeen at the jam. With them went 175 wagons, 11 ambulances, and 1,001 draught animals. To pass the obstruction the infantry had to turn widely out of the road and for a long distance push their way through the woods. No semblance of order survived. After this there was only one mass of men, wagons, and horses crowding to the rear.