...el General Polk was arrested to-day near Blandville, Ky., by one of the National scouting parties. He had despatches in his possession to spies at Columbus, Ky.--N. Y. Herald, January 14. The United States sloop-of-war Pensacola ran the rebel batteries at Cockpit and Shipping Points, on the Potomac, this morning, and reached the open sea without having been touched by shot or shell. A Reconnoiter...