Mary Emily Stewart
Mary Emily's death date, 29 March 1857, comes from the book "Peace Like a River," chapter 7. See FamilySearch: https://www.familysearch.org/photos/artifacts/29138688?p=10574233&returnLabel=Mary%20Emily%20Stewart%20(L4BB-C9R)&returnUrl=https%3A%2F%2Fwww.familysearch.org%2Ftree%2Fperson%2Fmemories%2FL4BB-C9R
Other secondary sources give her date of death as simply 1852. Further research is needed to determine the correct date.