Hi Kate,
My ggg-grfthr Patrick Herbert had a sister Maria Herbert. Maria married James Geraghty in RC parish of Moate/Mount Temple in 1840. James' name was spelled various ways in the records, including GARTY. James & Maria had three children baptized in Moate/Mount Temple that I have found - there could have been more.

Catherine, of James Geraghty & Maria Herbert, bap 27 Sep 1842; sponsors: Joane Harford & Maria Geraghty
Thomas, of James Gearty & Maria Herbert, bap 6 Dec 1846; sponsors: Bernard Gearty & Maria Gearty
Maria, of James Geraghty & Maria Herbert, bap 19 Jan 1852; sponsors: Thomas Kinehan & Bridget Geraghty

There were many more Garty/Geraghty etc. in this parish register. I only concentrated on James & Maria. Maria's two brothers came to Boston MA in 1870. Anything sound familiar with these names?
Sue