Re: Frances E. Slocum b.1855 in Boston.Ma.
I just checked every person named Frances listed in the two Slocum genealogy books and also checked for the name under the different Slocum spellings.I found a couple who's birthdate was close to what you had given, and secondly found a couple that either were associated with Massachusetts or were born in the close proximety of the Ma. area. The following is all that I could come up with.
Frances Elizabeth, born May 11, 1855, daughter of Capt. Aaron Case Slocum of Northville, New York. Page 418/19 book II and page 465 book I.
Frances Almeda, born January 26, 1852 in Fall River, Massachusetts. Page 289 book II and page 297 book I.
Frances S. born about 1855, daughter of Benjamin S. in Newport, Rhode Island. page 289/90, book I
Frances Slocum 8, born about 1857 in Iowa, but lived in Northhampton, Massachusetts in 1907.
This is all I can submit.Could Frances have been her middle name and her first name Elizabeth or something else ?
Trying hard, but keep striking out....darn.