You might like to have a look at http://www.pbs.org/wgbh/pages/frontline/shows/secret/famous/...
which talks about Dr. Thomas Galphin Holmes of Alabama, George Galphin and John Holmes (an Irishman who worked in the fur trade). There are a number of other refernces to George Galphin on the Internet including http://www.users.interport.net/~wovoka/aar99.htm
I have traced my line back to James Holmes who married Mary Kell in Liberty Co. GA in 1794. I believe his father was a John Holmes who moved to the Darien area in 1760 from SC. In the Midway/Sunbury area there were a number of Holmes family members at this time. A biography of Dr James Holmes of Darien (the above James's son) suggests they were related to Abiel Holmes of CT/MA (father of Oliver Wendell), who was the pastor of Midway in the late 1700s. One such family was :-
d. 1786 Hardwick, Bryan Co
David GALPHIN Holmes
(1785 - 1812 (Sunbury)) [Sunbury Militia]
m. 1805 Barbara Rankin ???
Frances Elizabeth (1808 - 1810)
Sarah Martha (1806 - ?) [Sunbury]
(m. 1826) Joseph Edward Maxwell)
+ one other sibling
I believe Barbara Rankin Holmes remarried in 1813 Charles Odingsell Screven (1773 - 1830). He was the son of James Screven.
Listed as Revolutionaries when Savannah was recaptured by the British in 1780 were :-
"George Galphin Rebel Superintendent of Indian Affairs".
"(Rev.) John Holmes late of the same Clerk".
"John Kell late of the same Gentleman". (Daughter married into my line).
"Lachlan Mc Intosh late of the same, Rebel General". (McIntoshes married into the Kells)
... and about 150 others.
I believe that Robert Holmes and John Holmes (my line who settled near Darien) could have been brothers. Evidence in my family line suggests they could have been from SC.
There was the following family in Charleston, about whom little seems to be documented, but were supposed to have moved to Georgia and Alabama :-
Isaac Holmes m. Susanna Poinsett (dau. Elisha Poinsett)
John Holmes 1729 -
Margaret Holmes 1731 -
Joel Holmes 1736 -
They do not seem to be directly connected to the extensive Holmes family descended from Francis Holmes of Boston and Charleston.
There is some further information on this at http://genforum.genealogy.com/holmes/
. Try searching the forum for the words Savannah, Poinsett etc.
If any light can be shed on untangling all this please email me, as I believe there is a connection to my line.