These photos show, I believe, Clara Elizabeth Bucklin (Shearer), 1857-1884, my grandmother's maternal grandmother, Isabel Clarke's mother. That makes her my children's great, great, great grandmother. The first print is particularly faded, dirty and stained. I made an attempt to clean it with PEC-12 but the cleaner did not do much.
This one is much cleaner but it has a painted look, which leads me to believe it is a retouched rendering derived from the same photographic source as the print shown above.
My grandmother's writing on the back reads "Mother of Isabel Bucklin Clarke, died 1883." Unfortunately this contradicts the notes in her journal, so I don't know which year is correct.