About your frustration with finding your O'Donnell people; look at more than one original record. A 19th C. handwritten capitol D can be easily confused with capitol D. Thus you may need to look at Donnell & Connell, O'Donnell & O'Connell, depending on handwriting interpretations. My experience has been that one of our Tipperary g-g-grandmother's maiden name was indexed as Donnell, which did seem to match the original registration (FHL-British Isles Film). However, her children's baptismal sponsors all included a male or female Connell (no Donnells). Baptismal sponsors were traditionally close family members, aunts and uncles. On a closer look at the whole page of registrations, capital D and C were written very much alike. Another backup was to review their neighbors in Griffith's Valuations to see which surnames popped up. My conclusion was that Connell dominated, thus more likely her maiden name. As a precaution, I look for both Donnell and Connell there, with 1 or 2 n's and l's, with or without the O' prefix. Best of Irish Luck, MMM