Mary,
My great great grandmother, Ellen Keliher McGillicuddy 1806-1866, seems to have changed the family surname to McGill when she arrived in America in 1845. At least two of her adult children retained the McGillicuddy surname. Many immigrants modified their surnames when they arrived in America. Their usual motive was to eliminate prejudices.
I have a record from Killarney, County Kerry from 1824 when Ellen married my great great grandfather John Mcgillicuddy. I have not been able to determine John's birth year. There were several John Mcgillicuddy's in Killarney who would have been of the correct age to have married Ellen. I have eliminated one or two of them but still cannot be certain that the John McGillicuddy in Darlinghurst was my ancestor.
I have recently located a John McGillicuddy in America who could have been Ellen's husband and my ancestor. But he was 15 years older than Ellen. I know such an age difference was not unheard of and am now re-evaluating my presumptions about him.
So, I would love to find a record by which I could either confirm or eliminate the John McGillicuddy at Darlinghurst. He fits all my known criteria.
Since the John McGillicuddy at Darlinghurst seems to have been a life prisoner and seems to have died at Darlinghurst, I assume he had no children in Australia. Today, all his descendants are in America, mostly near Boston, Massachusetts. Some of them are McGillicuddy's and others are McGill's.
Thank you again for your help,
Kevin McGill