Alexander Douglas, 9th of Mains

From https://deriv.nls.uk/dcn23/9528/95281270.23.pdf:

(400) Alexander DOUGLAS married Grizel, daughter of James Henderson of
Fordel, and had :

(a) Sir Archibald Douglas, married Isabel, daughter of Sir
George Elphinstone. Mentioned Great Seal Register
1643. Died s.p.m.

(b) Sir Robert Douglas, married the daughter and heiress of Sir
William Douglas of Blackerstone, and had a son James
(son of late Sir Robert), apprenticed Edinburgh 1665
{Apprentice Roll).