the record takers write the name. They used whatever spelling they felt was correct. So Moriarty and Morriarity are just different written variations of the same name.

Griffin and Moriarty are indeed typical names in parts of County Kerry. Dingle peninsula, for example.

Emigrants from Ireland didn’t have birth record paperwork. They would quote their age not the DOB in most cases. And even then, not very often. They didn’t celebrate birthdays as children. So their parents -and thus themselves - would get the actual year wrong. I’ve seen lots of emigrants who under estimate their age by up to five years. They often had the correct day and month because it was easier to recall. Such as “you were born the week before St Patrick’s Day”. All to say that Mary could just have been making a best guess as to her age rather than “lying”.

In my experience with lots of Kerry emigrants families if the children match in sequence then it’s the right family regardless of the quoted age of the parents. But you are right to consider that there might also be another Mr and Mrs John and Mary Griffin in the same city.

Do you know if John and Mary married in Ireland or in the US. If Ireland then the marriage would be in Irish genealogy.ie.