They left the immediate front of General A. J. Smith (who had with him a force of 4,800 cavalry and a large force of infantry and artillery), at Oxford, on the evening of the 18th instant and made a forced march hither, crossing the Tallahatachie River on a pontoon bridge at Panola, and arriving at our picket-line by 3 o'clock on the morning of the 21st. A force, consisting of about one-THIRD of Forrest's command, was detached by him and ordered to dash over the pickets and into the city, while the remainder engaged our forces outside. This detachment came in on the Hernando road, driving in the pickets and riding past a regiment of 100- days' troops that was there stationed, and rode with the utmost rapidity to my headquarters, which they at once thoroughly invested, giving me barely a moment's time to escape. Another party rode to the Gayoso House, where they expected to find Major-General Hurlbut, but in this were disappointed, he lodging that night with Colonel A. R. Eddy, assistant quartermaster. Another party went to attack General Buckland's headquarters, but making a mistake in the street, gave him also time to escape. They then proceeded to the Irving Prison, but the guard was ready for them and they were handsomely repulsed. By this time the provost guard had rallied and attacked the enemy vigorously, while the firing of the militia alarm gun added to the fright of the assailants, and they retreated as rapidly as they came, and joined the main force outside. They had no time for plunder, and save a few horses (perhaps 80 in all), they got nothing. Reaching the outside of the city a brisk fight was kept up with our forces there assembling until about 9 a. m., when the entire force moved off on the Hernando road. Our troops rallied rapidly to the point assailed, and under Colonel David Moore, Twenty- first Missouri Infantry, whose regiment was not present, but who volunteered, and Colonel G. B. Hoge, One hundred and thirteenth Illinois Infantry, commanding the remnant of his brigade, Lieutenant Colonel Roach, commanding One hundred and thirty-seventh Illinois Infantry (100- days' men), and Colonel E. L. buttrick, commanding Thirty-ninth and Forty-first Wisconsin Infantry (also 100-days' men), also Colonel Ray, commanding fortieth Wisconsin Infantry (100-days' men), with Colonel Prince, and the convalescents of the Seventh Illinois Cavalry, and Colonel M. H. Starr, and a small detachment of the Sixth Illinois Cavalry, they attacked vigorously and drove the enemy away. My effective cavalry was nearly all in the front with General Smith, but such as was here were ordered to fall upon Forrest's rear, and pursue and harass his retreat. They followed him to Hernando, twenty-five miles, which point he left, retreating toward Panola about 9 o'clock on Monday morning, the 22nd instant.

As soon as possible on the morning of the attack I endeavored to get a dispatch through to La Grange, to be expressed from there to Major-General Smith, but it was found that during the night the wires had been cut between Collierville and germantown. This was, however, repaired, so that by 12 m. I got through the following dispatch to General Smith:

Numbers 1. General SMITH,

Commanding Forces in the Field:

We were attacked at 3 o'clock this morning by a force of about 2,500 cavalry, said to be led by Forrest in person. The fight is still going on. They left Oxford two days ago and crossed he Tallahatchie at panola. You will at once order all your cavalry to move to intercept them. You will move one-half across at Panola and the rest at Abbeville. They must be cut off and caught. Move rapidly and spare not horse flesh. Their horses must be much jaded and they can be caught.

C. C. WASHBURN,

Major-General.