Thirtieth Missouri, who at once advanced within his 40 men, and gallantly attacked the rebels, driving them from the very start, so that they had no time to drive off the mules or do any damage to the pontoon train. General Gresham, commanding the post, sent over as fast as possible, with very limited means of transportation, the Ninety-fifth Illinois Infantry, the First Kansas, and the Seventeenth Wisconsin Mounted Infantry, and afterward the Eleventh Illinois Infantry.

The Seventeenth Wisconsin and the First Kansas were sent in pursuit of and moved against the enemy, who were retiring, with occasional skirmishing, across Cross Bayou, 16 miles in the direction of Trinity, where they came upon the main body of the enemy, abut 800 strong. This force, I am informed this morning (the 15th instant), is recrossing the Black River at Trinity.

The mounted infantry has been ordered to return, as they are considered entirely insufficient for any successful pursuit, as they are badly mounted and badly armed, and of very little use for any purpose whatever.

The force of the enemy is estimated at about 800, all cavalry. They are direct from Alexandria. Their object seemed to have been to capture the negroes recruited for Colonel Farrar's regiment and to destroy the pontoon train. The negroes, however, had all been transferred to this side of the river, except those doing picket duty, and the pontoon train was awaiting transportation.

Colonel Farrar, with the few men under him, attacked the enemy so vigorously that he had not time to accomplish his object, but was in full retreat twenty minutes after his first appearance.

I regret to say that 2 men of the pontoniers were killed, 2 were wounded, and 4 are missing. Captain Lochbihler, commanding pontoniers, was so severely wounded that his right arm had to be amputated. One of our men was also killed in the pursuit. The extent of the damage done the enemy is not known. One of their lieutenants and several men were killed in the first attack and left in our hands. We also captured 9 horses and several prisoners.

Great praise is due Colonel Farrar for the promptness, coolness, and courage with which he attacked the enemy with his small number of men. As the various detachments sent out have not yet returned, I am unable to send you an accurate statement of the casualties, but think I have stated the most of them. I will send a full report as soon as I receive the necessary information.

Very respectfully, your obedient servant,

M. M. CROCKER,

Brigadier-General, Commanding, &c.

Lieutenant Colonel W. T. CLARK,

Assistant Adjutant-General, Seventeenth Army Corps.

SEPTEMBER 15-OCTOBER 5, 1863.-Scout from Fort Wingate to Ojo Redondo (Jacob's Well), N. Mex.

Report of Major Eduard B. Willis, First California Infantry.

FORT WINGATE, N. MEX., October 6, 1863.

CAPTAIN: I have the honor to report that, in accordance with orders received from Lieutenant-Colonel Chaves, I left this post on Tuesday,