Thanks to Elwyn, Carolyn and Alex. Here's the problem. I have been researching for 40 yrs. I have my 3rd great grandfather Robert Russell in Haddington married 1810 to Agnes Amos. I havetheir ancestries and their 3 children. Agnes died in 1820 and Robert has 6 more children with a younger "wife" including my gggrandmother. The youngest of these 6 is born 1836. By 1841 the second wife is no longer with him. Apparently this second wife was Agnes Cameron.
According to notes written by descendants here in Canada, "...she left the old man and returned to Glasgow to live with her sister Jessie...". Further notes state "...she died in the 1870's in Glasgow.".
I have never found a second marriage record nor are there baptism records for the younger 6 children. 4 of these came out to Canada in 1853 and one went to Ireland. I am led to believe this was a common-law marriage.
There are a few Agnes Camerons in Glasgow in 1841 who might fit but unless I can find her with Robert in Haddington, I wouldn't know who to choose. Robert died in 1860 in Haddington and was buried at St. Mary's there. The grave marker was erected by his youngest son Thomas (born 1836) of Vancouver's Island. Also on the marker are Robert's eldest daughter Catherine (Croumbie) and her family.
You can understand the frustration because this elusive Agnes Cameron is my ancestor.