Maria is with her family in 1860 in Rochester, NY.
In 1870 she isn't with her father, his new wife and her sister Jessie. I don't know if she married or died.
Maria Antoinette Buchan, b. 6 Sept 1836, Rochester and d. 30 Aug 1865, Rochester.
Source: Rockwell Berry Family Tree, www.ancestry.com
but no sources are cited.
Buried: mount Hope Cemetery, Rochester, Monroe, NY
I'd look for her newspaper death notice. I'd contact the Monroe County Library System, www3.libraryweb.org/lh.aspx?id=963 who has an index to Rochester newspapers 1818-1897.
The Monroe County newspapers are on microfilm at the new York State Library, www.nysl.nysed.gov/nysnp/all/428.htm
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