Do you mean Philip Paul Bliss the hymn writer? Here's a page with info:
http://www.wholesomewords.org/biography/biorpbliss.html and another one at
http://pdmusic.org/bliss.html If so, Philip Paul Bliss is a descendant of the Rhode Island line of Bliss families and Helen McCray is a descendant of the Hartford line of Bliss families.
Here's what the genealogy by Ty Bliss shows:
Hartford Line
Thomas Bliss + Margaret Hulins
Nathaniel Bliss + Catherine Chapin
Samuel Bliss + Sarah Stebbins
Nathaniel Bliss + Mary Morgan
Pelatiah Bliss + Jemima Hitchcock
Zadock Bliss +Sarah Cushman
Zadock Bliss +Keziah Haskins
John Quncy Adams Bliss + Jane Weaver
Sarah Agnes Bliss + Millard Fillmore McCray
Helen McCray
Rhode Island Line
George Bliss + Ann Shaw
John Bliss + Damaris Arnold
William Bliss + Barbara Phillips
John Bliss + Reliance Babcock
Isaac Bliss + Lydia Doolittle
Philip Paul Bliss