I found the information on the combat at Salem, Arkansas. It is officially listed as Action at Spring River. It occurred on March 13 1862. The Union Forces involved were the 6th Missouri Calvary and the Third Iowa Calvary. Lt. Colonel Samuel L. Wood of the 6th Missouri Calvary was in command of 250 Troopers from the 6th Missouri Calvary and 130 troopers from the 3rd Iowa Calvary led by Major William C. Drake. The Union force left Missouri with the single purpose of preventing the formation of a full size Confederate Calvary Regiment from several understrength battalions, regiments and independent companies, mainly partisan rangers. Confederate Commanders were W.O. Coleman, J. Posey Woodside and Archibald MacFarlane.
The 6th Missouri Calvary was armed with a single cannon which was put to good use in the battle. From the description, the lopsided numbers of casualties on the Confederate side are a good indication that the cannon did its job. The Action lasted approximately 4 hours. Union casualties, 4 killed, 18 wounded 1 missing total loss of 23. The Confederate losses were not recorded, but Wood estimated a total loss of 100 killed wounded and captured.
The Third Iowa Calvary Adjutant described the battle as "one of the hardest consested engagements of its size in the West".