On March 18, 2011, I found the following information in the Mullingar library. The source is "A Partial List of Some Memorials in Westmeath Churchyards" by Micheal O'Conlain, page 456. Inscription found in Rathowen Parish, Rathaspick churchyard.
"Have Mercy O Lord on the soul of William DARDIS who departed this life 11 November 1788 aged 74 years with three of his children who died in youthfull innocence. Erected by his daughter Catherine TRAYNOR alias DARDIS"
Catherine Dardis Traynor is fully documented by information in the US (Franklin Co. TN Historical Archives) as the sister of James, Thomas, William(II) and Edward Dardis, therefore the William Dardis(I) referred to on the tombstone is the father of all of these siblings. Suggestions that the Irish parents of the Franklin/Knox County TN Dardis siblings are James Dardis (I) and Mary Wilson would appear to be incorrect.