Doyle:

It would help to know where Robert Parker lived prior to his enlistment.

A Robert Parker and a Pvt./Captain Wm. M. Hall are listed as members of Company C (raised in Leake County) in the 6th. Regiment which was also numbered the 7th. Regiment when received into Confederate Service.

The capsule history of the 6th. Regiment indicates the companies were mustered into the Confederate States' service for twelve months at Grenada, 24 August, 1861.
http://mississippiscv.org/MS_Units/6th_MS_INF.htm

Hope this helps,

Mitchell