WELLSVILLE, MO., January 2, 1862. Colonel J. C. KELTON, Assistant Adjutant-General, Saint Louis, Mo. COLONEL: I have the honor to urgently request the immediate action of the commanding general upon a matter which I regard of vital importance. Upon my arrival at Warrenton I found a battalion of Reserve Corps Cavalry under command of Major Hollan the only cavalry at my disposal. These men had preceded me only a few days but they had already murdered one of the best Union men in that vicinity and committed numerous depredations upon the property of peaceful citizens. Since that time their conduct has been absolutely barbarous-a burning disgrace to the Army and the Union cause. In spite of all my efforts to the contrary they have plundered and destroyed the property of citizens, many of them the best Union men in the State, to the amount of many thousands of dollars. Their officers either connive at it or else have no power to restrain their men. I cannot trust them out of my sight for a moment and of course they are of no use to me as cavalry so long as this is the case. I have succeeded in detecting five of the robbers and have them in irons, and have arrested the major and one of the captains and placed them in close confinement.   I have placed Lieutenant Sheldon, of my staff, in command of the two companies at this post, but I cannot long spare him from his proper duties and there are still three companies at other posts and it is beyond my power to prevent their acts of robbery if I make any use of them. No doubt there are some good men in this battalion but as a class they are well-armedand well-mounted barbarians. I am told there is at Benton Barracks a considerable force of good mounted men without arms. I therefore urgently request that a battalion of them be sent without arms or horses and that I be authorized to dismount and disarm Major Hollan's battalion and send it to Saint Louis. If something of this kind be not done soon there will be very few Union men in this part of the State. I will as soon as possible forward charges against Major Hollan, Captain Wenkel ad the men I have arrested. Very respectfully, your obedient servant, J. M. SCHOFIELD, Brigadier-General, Commanding.   SAINT LOUIS, January 3, 1862. Brigadier-General SCHOFIELD, Wellsville, Mo. GENERAL: Your letter of yesterday is just received. I have no cavalry to send in place of Hollan's command. As soon as you can dispense with this command send it back to Benton Barracks. If you think the officers and men who are in arrest had better be tried there I will order a military commission immediately on your sending the names of five officers suitable for such a court and one for recorder. If you think that they can better be tried here send all the prisoners and witnesses to this city where there is now a commission in session; but don't send them at the same time with the command. They will require a different escort. The offenses of each should be stated fully so that charged and specifications may be drawn up here. If their crimes are proved they will not be likely to escape punishment. Having all the witnesses there I think a military commission might dispatch the cases in a few days. I send you a couple of memoranda which may help you in finding out some of the bridge-burners. The names of the writers are known to me and are represented as reliable men. Very respectfully, your obedient servant, H. W. HALLECK, Major-General.