Griffiths is available on Ancestry.com (search the card catalog) or http://www.askaboutireland.ie/griffith-valuation/index.xml or http://www.leitrim-roscommon.com/GRIFFITH/

Familysearch.org is where I found John McManus's birth record. Make sure you allow for the variant of Brodrick.

Name: Johannes Mcmanus
Gender: Male
Baptism/Christening Date: 28 Jun 1856
Baptism/Christening Place: ST.PETERS, ATHLONE & DRUM, ROSCMN, IRELAND
Birth Date:
Birthplace:
Death Date:
Name Note:
Race:
Father's Name: Edvardi Mcmanus
Father's Birthplace:
Father's Age:
Mother's Name: Mariae Brodrick
Mother's Birthplace:
Mother's Age:
Indexing Project (Batch) Number: C70184-1
System Origin: Ireland-VR
Source Film Number: 989750
Reference Number: - 2:378VLZ3