From Georgia.
Griffin, September 21.
--One thousand of our men, including General Govan, were exchanged at Rough and Ready this morning, and a portion of them have arrived here.
The railroad is working through from Atlanta to Nashville, and is heavily guarded at all the bridges.
There are three brigades of negroes at Chattanooga.
Our prisoners met a great many of Sherman's men going back, but think he has still an immense army at Atlanta and along the railroad.