During the naval combat, General Banks marched three divisions of his army from Baton Rouge, to a point within seven miles of Port Hudson, where after engaging in a skirmish with the enemy, with trifling loss, they returned to their starting point. Being unprepared as yet to undertake the capture of Port Hudson, General Banks now turned his attention to that portion of the State west of New Orleans, and bordering on the Teche river. This diversion, it was afterward discovered, would have been made unnecessary, had General Banks possessed the means of learning the exact force of the rebels at Port Hudson, which was by no means so formidable as he had reason for believing. The Teche river is a tortuous stream rising in St. Landry parish, and flowing southwardly. On its bank are the towns of Franklin, Martinsville, and Opelousas. General Weitzel had previously made an unsuccessful expedition up that river, and to guard against further invasion a considerable rebel force was now posted in that region, and heavy earthworks were thrown up in the vicinity of Patersonville. The district of country bordering on the Teche, comprised the parishes of Terrebonne, Lafourche, Assumption, St. Mary, and St. Martin, rich in agricultural wealth, and having a large slave population. This district had furnished valuable supplies to the rebel army. OPERATIONS ON THE TECHE AND ATCHAFALAYA RIVERS, LA. APRIL 13–20, 1863. General Banks having concentrated his forces at Brashear, General Weitzel’s brigade was crossed over to Berwick on the 10th of April, without opposition, followed on the succeeding day by General Emory’s division, and both commands advanced upon the fortified position a few miles above Pattersonville. On the 13th, there was considerable artillery firing, in which the gunboat Diana, a late Federal capture, took active part. On the 12th, the division of General Grover left Brashear on the gunboats Clifton, Estrella, Arizona, and Calhoun, and transports, and proceeded up the Atchafalaya river, which joins the Teche at Berwick City, into Lake Chetimacha. The object was to get into the rear of the enemy, and if possible cut off his retreat if he evacuated his position, or to assail him in rear at the time of the attack in front. The expedition effected a landing early the next morning, about three miles west of Franklin, near a spot called Irish Bend. At this time, the gunboat Queen of the West, which had been captured previously by the enemy, was blown up and destroyed on the lake. Skirmishing immediately ensued with a small force of the enemy, that fell back as General Grover advanced. His position was about eleven miles distant from General Banks. BATTLE OF IRISH BEND, LA. APRIL 13, 1863. A correspondent in the army thus describes this battle: