In fact, if you look at the names of the Civil Parishes, you'll nearly always see that there's a R.C. Church with the same dedication not too far away. Off the top of my head, as well as St. Mary's, there's ...
St Andrew, St Nicholas, St James, St Michan, St Catherine, St Audeon .. (don't think there's St George!)
.. sometimes they're beside the Cof I church, sometimes the other end of the parish.
The Dublin Diocesan Directory is a useful book for finding out which and when R.C. parishes were divided/combined
regards eadaoin