There is a book by Iva Markey Kehr, Genealogy and History of the Jacob Markey Family of York County, Pennsylvania, 1750-1961. There is also a supplement called Supplement to A History of the Markey Family, 1961-1979.

It is possible that Jane Markey is descended from the Samuel Markey family of Baltimore County. Samuel's son Jacob moved to Hopewell Township, York Co., PA, in the early 1800s, nearby the ancestors of Abram McDonald:

Samuel Markey (b.1759 Baltimore Co., moved to Morrow Co.,OH in 1817, d. 5 Mar 1840, buried Bellville Cem., Richland Co.)
Elizabeth Singrey (b. 11 Oct 1760, moved to Morrow Co.,OH in 1817, d. 20 Jan 1847, buried Bellville Cem., Richland Co.)
     Jacob Markey (b. Abt. 1777 in MD, witnessed will of Christian Gore in Baltimore Co. on 16 Dec1802, moved to York Co., m. Elizabeth, shows up in 1840 and 1850 censuses in Hopewell Township with large household)
     Elizabeth Markey (b. 10 Sep 1788 in MD, d. 19 Feb 1861 in Richland Co.,OH, m. Martin Shaffer)
     John Markey (witnessed will of Christian Gore in Baltimore Co. on 16 Dec 1802, storeowner w/ same name in Morrow Co.,OH about 1835)
     Ann Markey
     Mary Markey (b. 26 Dec 1796, d. 16 Jun 1889, m. Jacob Wilhelm)

U.S. Federal Census Mortality Schedule 3 - Persons who Died during the Year ending 1st June, 1860, in Hopewell Township in the County of York. Line 5, Jacob Markey:

   Name: Jacob Markey
   Age: 80
   Sex: M
   Married or widowed: M
   Place of Birth: Md.
   The Month in which person died: Aug.
   Occupation: Farmer
   Cause of death: Paralysis
   Nuer of days ill: 11