Which came first the Irish or Sicilian Mafia?

from what I understand the Irish seem to have organized first in America coming from Ireland in waves after the potato famine.(1820-1840s) The term Mafia itself is from Sicilian but they don't seem to be organized into what is known as the "mafia" for some time later (1860s) Though I can't find anything to indicate who really came first. or did they form to counter each other in America.