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Baptismal records for Dromard parish start in 1823. My search on Roots Ireland did not locate a baptismal record for Michael. I also searched in Mayo and Sligo for a marriage record for Michael with no record. I searched 1825-1845. Many churches do not have records back that far so if they married in Ellen's church the records may not be available. Civil registration for RC marriages did not begin until 1864. Here is the link to the Dromard parish register http://registers.nli.ie/parishes/0746
I also looked on the 1828 Tithe records in Co. Sligo and found four Rowley records in Dromard parish. Possibly one of the four was Michael's father.