looks like at least a few of them are at Vicksburg..
Bailey, L.J. 16 Apr 1863 Pvt Co F 23rd WI
Douglas, D.M. 27 Dec 1862 Pvt Co K 23rd WVI
Hayden, L.H. 28 Mar 1863 Pvt CO I 23rd Vol
Williams, J.D. 1863 Pvt Co C 23rd WI Reg
http://www.nps.gov/archive/vick/natcem/nat_cem.htm