Preparations for an attack upon Vicksburg.
Mobile Dec. 26.
--The Advertiser and Register has a dispatch, dated Vicksburg, December 25th, which says the enemy yesterday landed a force on the Yazoo river; that skirmishing was kept up all day, with no loss on our side.
Warm work is expected to-day.
It is rumored that a number of transports reached the fleet last night.
[Second Dispatch.]
Grenada Miss., Dec. 26--Fifty transports, containing Sherman's troops, left Memphis at the end of last week for the South, and thirty more were to follow.
Every preparation, is being made for the defence of Vicksburg and the Yazoo river.
Grant's command occupy entrenchments left by our troops on the Tallahatchie, expecting an attack from the north.
Van-Dorn and Forrest are operating on their lines. 