Hello Joan,
John was the son of James Skillicorn (1819-1891) and Jane Quilleash (1829-1887), who married in 1861.
Further back, James was the son of John ( -1824) Skillicorn and Jane Kelly (1794-1860), who married 1813.
John was the son of Thomas (1751-1790) and Ann Kelly. Don't have any dates for Ann, nor the date of their marriage.
Thomas was the son of John (1724-1750) and Elizabeth Fargher (1721-1793), m 1750. (Elizabeth married second Philip Kinley).
John was the son of Thomas ( -1718) and Margaret Clark ( -1738), m 1718.
If you send me your e-mail address, I will send you details, including sources.
Lois