I stay pretty busy and thus don't have much time to search message boards like this (alas). My name is Terry White. I am the descendant of Wiley G. Marchman who in 1999 said that he was "definitely" a son of John Marchman of Henry County. My e-mail is email@example.com. Please contact me right away, so we can discuss this.
Here's why I'm so confident of Wiley's parentage:
The "M.G." Marchman who was the son of John (in the 1831 deed record) was in fact "W.G." Marchman (as you suspected). I didn't know this for certain until I had examined the original microfilmed deed (don't have a copy of it, however). Whoever transcribed that deed made a mistake in reading the "W" as an "M". (Easy enough to do.). Now, I also know that this was in fact "W.G." Marchman (and not "M.G." Marchman), because that land which John gave to his son in 1831 was 101 and 1/4 acres (or half) of lot 106, of the 8th District of Henry County. (The deed itself was recorded in Book F, page 30.) Turns out, that some thirteen years later, on Sept 17, 1844, "Wiley G. Marchman of Henry County" (exact wording) sold that entire land lot--number 106 of the 8th District of Henry County, to William J. Nisbit "of Newton County". (Book K, page 432)
Somewhere along the way, Wiley had obviously managed to pick up the other half of that land lot. I have always presumed it was due to inheritance after his father John's presumed death sometime in the year 1844, because it was in that year (apparently) that Wiley sold all his inherited and acquired Henry County lands, and moved to DeKalb (later Fulton) County. Wiley was in the 1850 census of Dekalb County, so he was certainly gone from Henry County by then.
This should conclusively prove Wiley's parentage. It does so to my satisfaction, in any case. I would appreciate it if you and others would cite my original research as the authority for this claim.
By the way, many years back I checked Ingmire's "Georgia Marriages" (and other such sources at the Georgia Archives) and never was able to find record of Wiley's marriage to Sarah Moore. I only found the date itself online (with no proof).
I'm descended from Wiley and Sarah's oldest child, who was born in Newton County (according to family tradition)--which was only about 1-2 miles across the South River from where Wiley and his father John lived at the time (in Henry County). For some reason, Wiley and Sarah apparently travelled across the river (and county line) for the birth. This daughter was Elizabeth Frances Marchman, the wife of Francis Marion White of Atlanta. Elizabeth was born on 24 Feb 1835 (tallies well with the reported marriage date of her parents), and died in Fulton County on 9 August, 1911. She and her husband are buried in Atlanta's ancient "Utoy Primitive Baptist Churchyard" (several websites exist showing photos of this place--look it up!). It is Atlanta's oldest cemetery--even older than the famed Oakland Cemetery where Margaret Mitchell Marsh lies buried. I am in personal possession of an original deed of the actual cemetery itself (I'm a member of the association that owns it). I have several photos of Elizabeth and her husband and children, and several photos and much data on the church where they're buried.
I have much, much more to add on these and related questions.
I very much look forward to hearing from you, and any other interested persons.
p.s., I only live five minutes away from the Georgia Archives, and only one county away from Fulton AND Henry Counties. I'm about an hour's drive from Carroll County.