I search 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.
For Catherine Kennedy B 1837 (exact) in Roscommon with a father named William, I found 1 B rcd. A view of the detailed rcd SHOULD show her parents' names. This clue might lead you to the M rcds for her parents. This in turn might lead you to their parents' names; thus, back another generation.
Pls post your search results to this genforum msg.