I presume this is the marriage you found for
James Seville marriage, 1871 Parish is St. Andrews RC.
The birth of James jnr would be before the start of Civil Records so you would need to to check parish records to try to locate his baptism and bridge the gap back to the 1828 marriage and his possible parents.
A civil record for the marriage should give you a little more detail, such as the father's occupations. These look like index references you need :
Name: James Seville
Registration : Dublin South
Event type: Marriage
Year: 1871
Volume : 17 / Page : 738
Name: Ellen Mooney
[same index references as James]
Shane
