...oc. 18.) Early this morning a force of Union troops under the command of Major Keenan, Eighth Pennsylvania cavalry, left Purcellsville, Va., on a reconnoitring expedition. They passed through Berrysville , Snickersville, and Philomont. On arriving at Union they found that town occupied by a battalion of Georgia cavalry, whom they drove out. Here it was ascertained that General Walker, in command of ...