And Helen Petrie on the 1881 census....
Dwelling: Newtongarry Croft
Census Place: Drumblade, Aberdeen, Scotland
Source: FHL Film 0203454 GRO Ref Volume 188 EnumDist 1 Page 9
Marr Age Sex Birthplace
William PETRIE M 69 M Drumblade, Aberdeen, Scotland
Rel: Head
Occ: Crofter 1 Acre
Margaret PETRIE M 51 F Kildrummy, Aberdeen, Scotland
Rel: WifeOcc: Crofters Wife
William PETRIE U 26 M Gartly, Aberdeen, Scotland
Rel: SonOcc: Farm Servant
Hellen PETRIE U 21 F Drumblade, Aberdeen, Scotland
Rel: DaurOcc: Servant
Jessie PETRIE U 15 F Drumblade, Aberdeen, Scotland
Rel: DaurOcc: Scholar
Ann PETRIE U 9 F Drumblade, Aberdeen, Scotland
Rel: DaurOcc: Scholar
James PETRIE U 12 M Drumblade, Aberdeen, Scotland
I see that the IGI has a Margaret Collie born 28th Apr 1828 in Kildrummy-

? as possible....