Samuel I. Green enlisted in 1861, Greene County, in Capt. Henry Roberts' Company (Gaines Warriors), Mississippi Volunteers. This company subsequently became Company A, 24th. Regiment Mississippi Regiment.

A capsule history of this unit is available at this link.
http://mississippiscv.org/MS_Units/24th_MS_INF.htm

Service records for this soldier are available at his site.
http://history-sites.com/research/index.html