I searched the Irish Family History Foundation's database. It contains 12,000,000 surviving rcds for abt 65% of Irish counties. Rcds are increasingly sparse B4 1840. Rare B4 1800. Co. Londonderry isn't in this database.
For the Northern Ireland counties in 1863 +/- 4 yrs, I found 0 B rcds for Phillip Clarkin. I get the same result when I search all Ireland.
Google the Foundation's name to lead you to this database. Pls post your search results to this genforum msg.