My grandfather, Daniel McNerlin, was a farrier who came to England from Derry in the early 1900's. His father, also Daniel, was also a smith/ farrier. His maternal grandfather, Joseph Barr, might also have a smith. My grandfather was born in Aghadowey, my great -grandfather in Articlave and my great-grandparents were married in Finvoy. My great-grandmother came from Kilrea. I have checked Pigot's and Slater's directories but can't find any mention of them. Is there a directory of smiths or any other record of the trade in Derry or Ulster?