JUNE 1-5, 1862.-Operations in Oregon County, Mo., and skirmish at Eleven Points.

Report of Colonel Conrad Baker, First Indiana Cavalry.

WEST PLAINS, MO., June 5, 1862.

SIR: The order of Major-General Curtis, of June 3, 1862, directing me to take position at Mount Olive with my whole command, consider myself temporarily detached from the First Division, and to report directly to the headquarters of the major-general commanding, was received this evening. I will to-morrow march south, concentrate the regiment, and take my position at Mount Olive as soon as possible.

I have just returned from an expedition into Oregon County, Missouri, where I marched in quest of a part of Coleman's gang without being able to find them. Some two weeks ago 3 soldiers of the Third Illinois Cavalry were returning home on furlough through Oregon County, and were fired upon by 6 or 7 armed citizens about 7 miles east of Thomasville. One of the soldiers, who is now here, was seriously wounded, and I have good reason to believe that the other 2 were taken and murdered. On Sunday last I sent out a foraging party, under Captain Deweese, to the neighborhood where this outrage was committed, with directions to take, if possible, dead or alive, the guilty parties. Captain Deweese arrived in the neighborhood of the assassins after night, and was fired upon from the house of one of them by 2 or 3 men, who in the darkness succeeded in making their escape after wounding severely one of Captain Deweese's men in the arm. Some 2 or 3 others of the band also fired upon Captain Deweese's men from the bushes near the house. Two of the bandits are said to have been wounded.

On the return of Captain Deweese, having understood that Coleman was in the same neighborhood, I started after night-fall on Monday, and made a forced march by night, arriving in the neighborhood about daylight the next morning, but information of our coming had, notwithstanding all the precautions I had taken to prevent it, evidently gone before, and the guilty parties were gone, and eluded all our efforts to find them. Coleman's band I am satisfied had not been there. I think the expedition, however, will be productive of good, as I made it my business to notify the entire neighborhood that if there was a repetition of these outrages the citizens would be held responsible, and might expect to be severely punished by the imprisonment of their persons and the destruction of their property.

I understand that Major Forth, of my regiment, who had command of a part of the regiment now in Izard County, Arkansas, has joined Colonel Marshall, of the First Illinois Cavalry, in an expedition toward Yellville. At the earliest practicable moment I will unite the regiment and take position at Mount Olive.

Respectfully, your obedient servant,

CONRAD BAKER,

Colonel First Indiana Cavalry.

Major H. Z. CURTIS,

Assistant Adjutant-General.