This post interested me as I have the surname Cumming (variants) who I believe emigrated from the Western Isles/Inverness-shire (Scotland), possibly to Nova Scotia or surrounding areas & possibly via Ireland.
I thought I'd do a quick check of the surname in my DNA matches' trees as I knew I'd come across the surname.
What a disappointment but now I know why I didn't follow it up.
This is one reason why people with DNA matches should never take/use info. from/on others' trees as fact!
INV = Inverness-shire (Scotland) - US = United States - WL = West Lothian (Scotland)
http://www.rootschat.com/links/01rpk/1719 - Margery Cumming was born in Inverness-shire, Scotland
1724 - Married John Bain Grant in INV, Scotland
They had numerous children (16) between 1724 & 1767
1726 - James - INV
1737 - David - US
1745 - Married John Bain Grant (again) in INV
1746 - Donald - INV
1747 - Peter - INV
1749 - Elizabeth - WL
1750 - Margery - INV
1752 - James - WL
1753 - John - INV
1756 - Richard - WL
1759 - Ann - INV
1760 - Elsbeth - INV
1761 - Elspa - Scotland
1762 - Alexander - INV
1763 - Nelly - INV
1766 - Janet - INV
1767 - Helen
CUMMING (not GRANT) - Scotland
Annie