Black Irish most certainly are known in Ireland. They are those descended from the mating of Irish and Spanish, (the women are utterly beautiful - black hair, olive toned skin and blue eyes). Many old artifacts and ruins can be found in Ireland, especially on the west coast, attributable to the Spanish.
That's what I was always told by the Irish side of my family.
Not being an expert at anything, my comment came from “the deep dumb wisdom of the race” (all that stuff we assume to know because that’s the way we were told.
I stand newly informed.