"Boston, a Negro" was baptized as an adult on February 8th, 1756 "in the first Church of Christ in Wells, upon ... having made a Personal, Express, Publick Profession of Christianity."
Intention of Marriage filed in Wells on August 31, 1754: "Boston, Negro servant to Mr John Littlefield of Wells to Florah, Negro servant to Mr Jedediah Morrill(?) of Berwick"
It has not been confirmed that the Boston who was baptized (as an adult in Wells in 1756) was the same Boston who filed a declaration of intention to marry Florah (in Wells in 1754), but that is the assumption made here.
Bibliography:
Records of the First Church of Wells, as transcribed in 6 issues of the New England Historical and Genealogical Register, Vol 75-76, 1921-22
Maine Vital Records, 1670-1921