Attached is the 1870 census for Peter Dub, wife Barbara, & their children Peter and Barbara, and most likely wife Barbara's father Anton Mark.
Peter Dub is listed on page as what looks like Tubb.
Peter Dub is indexed in the census as "Teibb."

1870, IL, Cook county, 6th Ward, Series M593, Roll 201, Page 317.

(Peter, son of Peter & Barbara, later married Mary Ann Martin, listed on page 319)

No wonder it took me four years to find him !!! Who would have thought that DUB would be indexed as TEIBB !!!