By dawn the next morning, at all events, Banks calculated, the turning column would be in place; accordingly during the night he gave orders to assault along the whole front as soon as it should be light enough to see.
However, shortly after midnight, sounds were heard on the picket line, indicating some unusual movement behind the Confederate works. When, at daybreak, the various skirmishers moved forward in eager rivalry, they found the Confederates gone. Captain Allaire, leading his company of the 133d New York, was the first to enter the works; the regiment itself and the 8th New Hampshire followed closely, and the colors of the 8th were the first to mount the parapet, where they were planted by Paine. On the left bank, this honor fell to the 53d Massachusetts. But in truth the surge was so nearly simultaneous that the whole line of entrenchments on both sides of the bayou, from right to left, was crossed almost at the same instant.
It was nine o'clock on Monday night when Taylor learned of Grover's movements and position, as narrated in the next chapter. Taylor at once began to move out of the lines of Bisland and to direct his attention to Grover in order to secure a retreat. Just before daylight Green, to whom, with his 5th Texas, Waller's battalion, and West's section of Semmes's battery, Taylor had given the more than usually delicate task of covering the rear, marched off the ground, leaving nothing behind save one 24-pounder siege gun and a disabled howitzer of Cornay's battery.
Without losing an instant the pursuit of the retreating Confederates was begun, Weitzel leading the way, and was conducted with vigor and with scarcely a halt, notwithstanding the energetic opposition of the Confederate rear-guard, until early in the afternoon, just beyond Franklin, Emory's advance guard, under Paine, following the bayou road, ran into Grover's under Dwight, approaching from the opposite direction. Weitzel, having entered Franklin without opposition, kept the left-hand or cut-off road until he came to the burnt bridge over the Choupique, by which, as will presently be seen, the Confederates had escaped.
Gooding, after occupying the works in his front, crossed the Teche by a bridge to the west bank and fell into Emory's column behind Ingraham. The Clifton, as soon as the obstructions could be removed, got under way and moved up the bayou abreast with the advance of the army.
The losses of the Nineteenth Army Corps in this its first battle were 3 officers and 37 men killed, 8 officers and 176 men wounded; in all 224. The 38th Massachusetts headed the list with 6 killed and 29 wounded, and Gooding's brigade, to which this regiment belonged, reported 87 casualties, or 38 per cent. of the whole. In the six light batteries 15 horses were killed and 12 wounded, and one caisson of the 1st Maine was upset and lost in crossing the Teche to go into action.
The losses of the Confederates have never been reported and no means are known to exist for estimating them.
The disparity of the forces engaged was more than enough to overcome the Confederate advantage of position, for Banks had 10,000 men with 38 guns, while Taylor reports but 4,000 men with four batteries, estimated at 24 or 25 guns. To these must be added the Diana, until disabled on Monday morning, and to the Union strength the Clifton, after she arrived and opened fire at long range on Monday afternoon.
At Bisland the new headquarters flags were for the first time carried under fire. These distinguishing colors, as prescribed in General Orders on the 18th of February, were guidons four feet square attached to a lance twelve feet long, made for convenience in two joints. In camp or garrison they served to indicate the quarters of the general commanding the corps, division, or brigade, while on the march they were borne near his person by a mounted orderly, commonly a trusty sergeant. The flag of the Nineteenth Army Corps was blue with a white four-pointed star in the middle, and on the star the figures 19 in red. From this the division flags differed only in having a red ground and the number of the division in black. The brigade flags had blue, white, and blue horizontal stripes of equal width, with the number of the brigade in black in the white stripe. Thenceforward these colors were borne through every engagement in which the corps took part. Not one of them was ever abandoned by its bearer or taken by the enemy.