I also have two women in my family tree who married men with the last name of Marcus (or Markus) from Vieksniai, in US records written as Vexna or Wexner. One of the men was named Jacob Marcus, and the other Harris Marcus (probably originally Hirsh or Aaron). These couples settled in Boston, Massachusetts in the early 1890s. I also have not found any records of these men or their wives on Jewishgen. From Jacob's gravestone, his father's name looks possibly to be Yechiel Zvi.
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Michele Lock
Lak/Lok/Liak/Lock and Kalon/Kolon in Zagare/Joniskis/Gruzdziai, Lithuania
Lak/Lok/Liak/Lock in Plunge/Telsiai in Lithuania
Rabinowitz in Papile, Lithuania and Riga, Latvia
Trisinsky/Trushinsky/Sturisky and Leybman in Dotnuva, Lithuania
Olitsky in Alytus, Suwalki, Poland/Lithuania
Gutman/Goodman in Czestochowa, Poland
Lavine/Lev/Lew in Trenton, New Jersey and Lida/Vilna gub., Belarus