The Federal forces at Berwick advanced to Vermilion bayou on October 8th, and were at Carrion Crow bayou three days later. The expedition was composed of eleven brigades of infantry, two of cavalry, and five battalions of artillery, all under Maj.-Gen. W. B. Franklin. On October 21st General Taylor was compelled to withdraw from Opelousas to Washington. A raiding party sent to the enemy's rear, under Col. W. G. Vincent, returned with prisoners and signal books containing important information. This information assured Taylor that Franklin's object was not Niblett's Bluff, but his army. An elaborate plan had been made, it appeared, to encompass him from Sabine Pass and Morganza, while attacked in front from Berwick. But knowing that the first two movements had been foiled, Taylor felt confident of defeating the third. On the 24th, when the enemy advanced five miles above Washington, Taylor drew up his forces in line of battle to meet him, but the Federals declined battle and fell back to Washington. A few days later it was discovered that Franklin was in full retreat, and Taylor's cavalry went in pursuit. General Washburn reported November 2d, ‘We had a pretty lively time to-day.’ In a later report he stated that on the 3d he heard a rapid cannonading, and riding back, found ‘that we were assailed by an overwhelming force in front and on both flanks. Many of the troops had been broken and were scattered over the field, and the utter destruction or capture of the whole force seemed imminent. ... Our losses are 26 killed, 124 wounded and 566 missing.’ This engagement, known as Bayou Bourbeau, was fought by Green's cavalry division, and victory gained with a loss of 22 killed and 103 wounded. On the 4th General Mouton reported the enemy at New Iberia. ‘Colonel Vincent ambuscaded them at Nelson's ’
