I don't know anything about my ancestors having an Irish connection. Am I related to your John's elder brother James?
All I know is that my gg grandfather was James Maxwell born 1834 in Scotland, the son of James Maxwell and Elizabeth Alexander (No other information on parents or siblings).
My James married Susan Pollock 1859 in Cambusnethen, Lanarkshire, Scotland. They had 7 children, 3 of whom died in childhood and are buried in the Cambusnethen graveyard. The rest of the family emigrated to the United States I believe in the early 1880s.
cmortimr at yahoo