The FAG for her father says:
Ephraim McDowell was born in Londonderry, Ireland in 1673 and married his first cousin, Margaret Irvin who was the daughter of Robert and Margaret Wylie Irvin.
I see the trek her on Geni shows them as married but they are not showing as first cousins (yet)... most of the time I see a statement of first cousins marrying, I can find the relationship here on Geni but it has not appeared yet or the statement is incorrect.
https://www.geni.com/path/Ephraim-McDowell+is+related+to+Margaret-M...
