The original image with full details on their parents' names is available to view on www.scotlandspeople.gov.ukDuncan gave his place of birth as Tomintoul in Banff. This is in the parish of Kirkmichael. There is this 1851 census entry that might fit for him:Janet Cumming 34 general servant unmarried b. Tomintoul Kirkmichael, BanffshireBetsy Ross 8 daughter b Kirkmichael, BanffshireDuncan Ross 6 son b. Kirkmichael, BanffshireAddress: Main Street Krkmichael Tomintoul-BanffshireRose and Ross can be interchangeable.Monica
So Janet could possibly be their mum? Strange in those days being not married..