I am thinking that in my family, which emigrated to the US just post famine, the naming pattern ws replaced.  They still used family names, but the names seems to be those of relatives who were also in this area.  Example:  My ggrandmother's first daughter was named for her sister, and her second either for herself, or in my theory for her aunt who was here and very good to her.  My ggrandfather's first son was named for the person he lived with when he came--I believe that to be an older brother.   Kathleen