Marks Mill. One hundred picked men under Lieutenants Greathouse and Young were then dispatched to destroy the Confederate pontoon bridge at Longview. On March 29, the lieutenants surprised and captured approximately 250 soldiers belonging to Brig. Gen. Thomas P. Dockery's brigade at Longview. Confederate forces in the area were now alerted to the presence of Clayton's raiders in the area and attempted to cut off Clayton's command by attacking their bridgehead at Mount Elba on March 30, 1864. Clayton was successful in re-crossing the Saline, defeating Confederate forces at the Battle of Mount Elba and returned to Pine Bluff, Arkansas, with over 260 prisoners. The first Union actions of the Union expedition was a complete success, but the rest of the expedition would not go as planned. Engagement at Elkin's Ferry Steele's route was through a thinly populated wilderness with little provisions. He hoped to occupy Camden, a port city on the Ouachita to re-supply. As all the bridges on the Little Missouri were impassable, the Union troops had to ford the muddy river. Steele's men reached Elkin's Ferry before the Confederates, but on April 3, they were attacked by Brig. Gen. Joseph O. Shelby's cavalry. The following day, Marmaduke's cavalry also attacked the Union forces as they were trying to cross the river. The Federals were able to fend off both of these attacks and then cross the river. The outnumbered Confederates were forced to withdraw, and Maj. Gen. Price established a defensive position, lightly fortified by earthworks, on the road between Elkin's Ferry and Washington at the western edge of the sparsely-populated Prairie d'Ane, a roughly circular area of prairie surrounded by woodlands. Skirmish at Prairie D'Ane After waiting for the arrival of reinforcements, Maj. Gen. Steele advanced on April 9, but was stopped at Prairie D'Ane, a series of encounters that ended on April 12. Price's Confederates returned to Prairie D'Ane on April 13, falling upon Steele's rearguard under Thayer. After a four-hour battle, Price disengaged, and Steele's column continued to Camden. Steele made a feint toward Washington, but then withdrew to Camden, in order to resupply his army, which was then on half-rations. Price had stripped Camden of personnel in order to defend Washington, and the Union forces occupied the city on April 15 against no significant opposition, but found no supplies awaiting him. Engagement at Poison Spring After a two-day wait, Maj. Gen. Steele sent