Mark:
I checked Roots Ireland www.rootsireland.ie and they have Knockainy RC records back to 1808. I could not locate the marriage record for James and Mary but possibly they were married in a different church.
I did search for baptismal records for Riordan children from 1810-1830 in the Knockainy RC records where the parents were James and Mary Cleary. There were seven records.
Roots is a pay site and they now require that you purchase a subscription in order to view the transcriptions of church records.
Roger McDonnell