It sounds like Dardanelle was being used as a personnel holding area:

"McRae's brigade, and was, on the march from Fort Smith, [Arkansas] sent to Dardanelle [Arkansas] to protect the public property at the latter place. He has since been ordered to this place, and is now on the way down on the s south side of the river, having been relieved at Dardanelle by the non-effectives of [Charles A.] Carroll's brigade, and [John S.] Marmaduke's Division. "

"I instructed Gen'l Marmaduke, by telegraph, to .... His non-effectives numbering three or four hundred under command of Lieut Col [Merritt L.] Young were left by him, at Lewisburg [Arkansas]. I ordered them, recently, to Dardanelle [Arkansas] as instructed by the Lieut General Commanding, to which place they have proceeded.