I am going to send you what I ahve here at the house from the Grace Ref. records on the Gerhart name.
Henry born April 19, 1803
John born Jan. 10, 1805
David born March 9, 1806
Anna Maria born June 18, 1807
Catherine born Dec. 29, 1808
Jacob born Oct. 14, 1811
Rebecca born March 4, 1817
Sophia born July 29, 1818
All these children were bapt. Nov. 12, 1819 & the parents were Jacob & Margaret Gerhart
I do know that there were two Gearhart families in Antrim during that time, Jacob & Andrew. Andrew was married to Jane Carolus. Their daughter, Josephine, married David Gearhart, son of Jacob and they named a daughter, Julia, born 1871. Andrew lived near Guitner's U B church, NW of Greencastle & Jacob south of Greencastle.
I don't have the 1840 census index or the 1843 tax list here at the house but that would be a good place to see what Gerhart's were in Franklin County right before the marriage. I will try to remember to check to see if there are records at the church or a newspaper marriage.