I am also doing genealogy on the Hazelton line.I have a Marcy (Mercy) b. 16 Aug 1642. Father was Robert b.1615 mother was Ann? d: 26 Jul 1684 in Bradford, Essex, Mass. They were married 23 Oct.1639 in Rowley, MA. Had 7 children: Anna, Marcy(Mercy), David, Mary, Abraham, Deliverance and Eliz. There is also a Hazeltine Geneaology book you might be interested in.Contact me.