There is lots posted on the internet for your ancestors who were Mennonites from Buck County, Pennsylvania & who came to Ontario.
See WorldConnect:
http://wc.rootsweb.ancestry.com/Your James was the son of Staats Overholt & Matilda Phillips. Staats Overholt was the son of Staats Overholt & Sarah Cornelius; the latter Staats was the son of Jacob Overholt and Susannah; Jacob was the son of Statts Overholt & Susanna Hunsberger; the latter Staat's was the son of Mark/Marcus Overholt and Elizabeth Staats; Marcus Overholt was the son of Samuel & Elizabeth
The Upper Canada Land Petitions for the Overholt family is posted here:
https://sites.google.com/site/niagarasettlers/petitions-oName: Stawts Overholt
Birth Date: 1835
Birthplace: Canada
Age: 24
Spouse's Name: Matilda Phillips
Spouse's Birth Date: 1840
Spouse's Birthplace: Canada
Spouse's Age: 19
Event Date: 30 Nov 1859
Event Place: Baptist Church, Woodstock
Father's Name: Stawts Overholt
Mother's Name: Sarah (my note - nee Cornelius)
Spouse's Father's Name: Stephen Phillips
Spouse's Mother's Name: Rebeka
Name: Statts Overholt, father of your Staats
Event Type: Death
Event Date: 15 Jan 1873
Event Place: Charlotteville, Norfolk, Ontario
Gender: Male
Age: 76
Birthplace: Canada
Birth Year (Estimated): 1797
informant: Joseph Overholt of Charlotteville
http://ontariomennonitehistory.org/2015/01/12/were-the-early...1900 US Census Richfield Tp., Genesee, Michigan
Stauts Overholt Head M 63 b. Mar 1837 Canada E, father b. Pennsylvania, mother b. Ireland, immigrated 1887
Matilda Overholt Wife F 60 b. June 1840 Canada E, father b. New Brunswick, mother b. Canada
Ida Overholt Daughter F 15 b. May 1885 Canada E
Death register - Seeking Michigan -
http://seekingmichigan.contentdm.oclc.org/cdm/singleitem/col...His age is listed as 69yrs 2 months & 26 dys; date of death May 26 1906 = born February 1837; father's name was the same as his and he was also born in Canada; He was a Minister
http://seekingmichigan.contentdm.oclc.org/cdm/singleitem/col...Matilda's birth date was given as June 20 1840; she died July 18 1914; father - Stephen Phillips b. Canada; mother - Rebecka Flood b. Canada; informant Ezra Overholt of Davidson, Michigan