When I looked back at the old thread re Caroline Reid, I recall that neither myself or Monica could find very much on her mother Caroline Matilda Ferguson.
Both of us assumed that she could be Irish.
I'm certain that her birth was not on Family Search at 2013 but it's there now!
Caroline Matilda Ferguson b 17 Oct 1820 Old Cumnock
Parents Alexander Ferguson and Agnes McKnight.
Her sister Jane Ferguson b 29 Dec 1824.
Married Thomas Ritchie before 1851
The only census I can find
1851:Daleagles, New Cumnock
Thomas Ritchie 26b Leadhills, Lanark. Coal Miner
Jane Ritchie 26 b wife B Old Cumnock
Agnes Fergurson 55 Mother in Law b Straiton,Ayrshire