What fun to see your message. I used to correspond with Alice Eichert, who gave me lots of information on this branch of the Hartwell family, which was entirely neglected in the 1958 genealogy.
Mary Elizabeth "Molly" Hartwell was born probably in Cincinnati, OH ca. 1835 and died at Washington DC 10 Jan. 1908, daughter of George Henry & Eliza (Athearn) Hartwell. She never married, but had several nieces and nephews. I can give you the whole family if you want.