Dear John, The wife of James Parkhill Sr. is most likely Jean/Jane Laird, daughter of John Laird and Agnes Black (dau. of Hugh Black) of Derry twp, Lancaster (now Dauphin) PA. “Jean Born ye 12th of October and 6th of ye moons age A.D. 1752 Near 12 O Clock on Thursday” (Bible Record of John Laird and Agnes Black) Jean's sister Mary Laird married Andrew Bigger, and the two sisters were living in the same Peters, Franklin PA neighborhood starting in the 1790 census, for at least until 1830.(There is also a James Black, but I do not know if he is a cousin or not.) And you will find James Bigger living a few doors away from Elizabeth Parkhill in Guensey OH. in 1850.
The Lairds, the Chambers, the Blacks, and the Bells can all be found together in the early tax records of Derry twp. Contact me if you want more info.