Affairs on the Rapidan.
Orange C. H., Dec. 7.
--The previous reports of the enemy retiring behind the Rappahannock are confirmed by later intelligence.
They are tearing up the railroad between the Rappahannock and Rapidan rivers.
Large wagon trains were seen moving down between the two rivers yesterday.
They have some camps around Stevensburg, Culpeper county, and their cavalry pickets extend to Mitchell's Station, four miles north of the Rapidan.