"Joseph Hobbs had two [enslaved people], Zelph and Phillis." - Bourne, p. 407
Shelley (p. 153) states "Joseph Hobbs had Zelph and Phyllis baptized." However, these two baptism records are not included in the 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.
The 1790 US Census for Wells lists Joseph Hobbs with one "other free person." This could have been Zelph or Phillis.
Bibliography:
The History of Wells and Kennebunk from the Earliest Settlement to the Year 1820 - by Edward Bourne (1875)
My Name is Wells - by Hope M. Shelley (2002)