My father’s brother Sam Stack married Hilda Marcus.
They believed that they were 3rd cousins in the Slotnick line.
From the tree in Ancestry posted by Shoshona Marcus (with whom I have not been in touch):

1 Rojza Mina Zlotnicki b: 1850 in Nowy Dwor, Maz, Poland d: 1912
.. +Eliezer Ze'ev Lejzer Wolf Elfenbejn b: 19 Oct 1850 in Nowy Dwor  d: in Nowy Dwor
..... 2 Rebecca (Toba Rifka) Elfenbeym b: 11/6/1873 Nowy Dwor, Maz, Pol d: 1945 Boston, MA
......... +Alick Alexander Elick Marcus b: 1894 d: 1955
............ 3 Hilda R. Marcus b: 09 Jul 1900 in Poland d: 06 Jan 1995 in Roslindale, MA
................ +Samuel H. Stackowitz b: 3/26/1895 Warsaw  d: 2/5/1985 Stoughton, MA m: 1923-1924 Boston

My tree. Is Rojza-Mina (above) a sister to Sarah (Sura Krajna)?

1 Shmul Zlotnicka b: c1818
. +Rukhlya Pokornyj b: c1825-10/24/1872 Nowy Dwor
.... 2 Sarah Sura Krajna Zlotnicka b: Bet. 1846 - 1851
........ +Mathew Mattias Matityahu Nosan HaLevi Stasiovich b: 10/27/1855 Zakroczym, Pol. m: 8/17/1871 Nowy Dwor, Pol
........... 3 Isaac Stasiovich Stachowitz b: 15 Jun 1875 in Warsaw, Poland d: 22 Sep 1948 in Lewiston, Maine
............... +Ethel Oldstein b:1/8/1872 Nowy Dwor, Maz, Pol d:3/1/ 1949 Lewiston, ME, US m: cNov 1891 Pol
.................. 4 Isadore Stackowitz b: 17 Jan 1910 Brooklyn, NY d:1/20/1970
...................... +Anne Thorner b1/30/1916 Brooklyn, d: 5/24/2012 Houston, TX m:10/12/1944 Biddeford, ME
......................... 5 Barbara Toby Stack b: 29 Jul 1947 in Dover, NH THIS IS ME

March 15, 1863 Birth of Icek Zlotnicky in Nowy Dwor. Recorded Oct. 6, 1884
translated by Marina Podrabinnik. Many thanks!
Sarah's younger brother

71.
It happened In October 6th, 1884 in 10 AM in town Nowy Dvor. Shmul Zlotnicky, worker, living in Nowy Dvor, 66 years old, personally came in and presented baby boy. He announced that baby boy was born to him and his deceased wife Rukhlya Pokornyj on March 15th 1863 at 2 PM in Nowy Dvor. During religious ceremony baby boy was named Icek. Leib Yunker, 60 years old, shkul'nik (have no idea what it means), and Shoysel' Stashevich, 50 years old, worker, both from Nowy Dvor, witnessed announcement. First witness signed the record. Government official had to read this record to father and second witness because both of them were illiterate.

January 21, 1876 Marriage of Icek Zlotnicki & Frymet Statszowicz. Recorded March 20, 1884.
gift of Ellen Stack. Many thanks!
Sarah's younger brother

15.
At the town of Nowy Dwor, date March 20th 1884, came two men
Haim Siglovitc and Lyb Yudkevitc and declared that they were
witnesses in the religious marriage of Icek Zlotnicki, bachelor
age 18, son of Samuel and Ruha,
And the bride Frymet Statszowicz, age 18 daughter of
Moshe and Byla.
The marriage took place at January 21st 1876.
The parents of the couple came with the witnesses.
Prior to the marriage there were 3 publications at the synagogue
That the couple wishes to get married.
There were no objections to this wedding.

October 24, 1872 Death Rukhlya Zlotnishchka
gift of Aaron Slotnik. Many thanks!

Left margin: 107.

1. [It] happened in city Novyi Dvor twenty
2. sixth [of] October thousand eight-hundred seventy sec-
3. ond year at nine o'clock [of] morning, personally appeared Eliyash
4. Itsek Segalovich, sixty eight years and Leib --
5. Yunker forty eight years, both Novodvorskii Synagogue
6. Scholars, [they] announced, that twenty fourth [of] Oc-
7. tober [of] this year died in city Novyi Dvor
8. Rukhlya Zlotnishchka, at four o'clock [of] morning, forty
9. seven years from birth, daughter [of] Vulf and Mina from Gersh-
10. koviches spouses Pokorn. By death hers
11. [she] left husband Shmul and three minor
12. children, property none;_ Per personal verification
13. about death [of] Rukhlya Zlotnishchka, Act this per
14. reading [by] us [by] witnesses was-signed.

15. Ea.* [of] Burgomistr [of] Novyi Dvor
16. Maintaining books [of] Civil E. I. Sigalowicz (latin)
17. Status Affanasovskii Lejb Junkier (latin)

August 17, 1871 Marriage  Matys Stasiowicz and Sure Krajna Zlotnick trans. by Tonya Staros
many thanks, Tonya!

#25
1. Happened in the town of Novyi Dvor on the day of eightee-
2. nth of August of One Thousand Eight Hundred and Seventy First
3. year, at two o'clock in the afternoon. Personally came Faivel'
4. Barab the rabbi of the town of Novyi Dvor, together
5. with a Jew Matys Stasiovich bachelor
6. eighteen years old, in the town of Novyi Dvor resi-
7. ding, the son of Shepil' and Bayl Nysonovicheva
8. the couple Stasiovich being alive and
9. a Jewess Sura Kriyna Zlotnitskaia maiden
10. from Novyi Dvor, twenty years of age, the daughter of Shmul'
11. and Ryfka Pehornyh the couple Zlotnitski
12. being alive, witnesses present were
13. Eliash Ith Segylovich age sixty seven
14. and the life cadet, forty seven years old, both from Novyi Dvor,
15. Shkol'nikov, announced that on the seventeenth
16. of this August there was performed a lawful
17. marriage between the Jew Matys Stasiovich
18. bachelor and the Jewess Sura Krayna
19. Zlotnitskaia, maiden, this marriage before
20. it was performed was three time announced in the Syna-
21. gogue of the town of Novyi Dvor, namely: on the seventeenth,
22. twenty fourth and thirty first
23. of July of this year, against this no
24. objections followed. This marriage
25 was performed with the spoken agreement of the parents
26. of the groom and the bride. At that point
27. the newlyweds announced that they are not signing
28. a prenuptial agreement. Then the act
29. was announced to the newlyweds and the witnesses
30. the rabbi and the witnesses
31. signed. The newlyweds announced that they
32. can't write.
33 Mayer ...
34?
35 ? Fredirovich

My father’s brother Sam Stack married Hilda Marcus.
They believed that they were 3rd cousins in the Slotnick line.
From the tree in Ancestry posted by Shoshona Marcus (with whom I have not been in touch):

1 Rojza Mina Zlotnicki b: 1850 in Nowy Dwor, Maz, Poland d: 1912
.. +Eliezer Ze'ev Lejzer Wolf Elfenbejn b: 19 Oct 1850 in Nowy Dwor  d: in Nowy Dwor
..... 2 Rebecca (Toba-Rifka) Gilfenbain Elfenbein Helfeinbein b: 11/6/1873 Nowy Dwor, Maz, Pol d: 1945 Boston, MA
......... +Alick Alexander Elick Marcus b: 1894 d: 1955
............ 3 Hilda R. Marcus b: 09 Jul 1900 in Poland d: 06 Jan 1995 in Roslindale, MA
................ +Samuel H. Stackowitz b: 3/26/1895 Warsaw  d: 2/5/1985 Stoughton, MA m: 1923-1924 Boston

Birth Record for Tauba-Ryfka Elfenbejm.   November 6, 1873
Courtesy of Elaine Ostrach Chaika, from Terry Ostrach Chase from Ken Marcus.

109. Fact in the town of Nowy Dwor on November ten one thousand eight hundred and seventy-three at ten o'clock in the morning. With appeared in person the Jew Lejzor-Vulf Elfenbejm, workman twenty-four year old, regular inhabitant of the town of Nowy Dwor, in the presence of witnesses: Elijash Itsk Sigalowicz, sixty-nine years old and Lejb Junkier, forty-nine years old, both members of the " Pieuse" patrols; [1]; it introduced to us a child of female sex, born in the town of Nowy Dwor on November six from this year, at six o'clock in the morning: his child and that of his wife, Mina née Zlotnicki, twenty-three years old; it was given to this child the name of Tauba-Ryfka. The witnesses signed this act after reading of this one, the father declared that he could not write. Fulfilling the function of Burgomaster of the town of Nowy Dwor, person in charge of the behaviour of the registers of l' Civil statue: XXX E.J. Sigalowicz Lejb Junkier

Certificate of marriage between Eliasz Markiewicz and Taube Ryfka Elfenbejm.   May 18, 1900
Courtesy of Joachim Modern via Terry Chase.

Elias Markowicz & Tauba Ryfka Elfenbejm  Marriage Certificate
Marcus-Gilfenbain

24. Novy Dvor, May 19th 1900 at 10 AM personally appeared Novy Dvor Rabbi Khaim-Mendel Landau together with Jew Eliyash Markovich, 25 years old, son of Falek Gersh and Ginda, born Kon, permanent resident of (not clear) Pultusk District, temporary living in Novy Dvor, with Jewess Tauba-Ryfka Elfenbejm 26 years old, daughter of Lejzer Vulf and Rojza-Mina, born Zlotnitsky, residents of Novy Dvor and declared that yesterday at 10 PM in presence of witnesses [names, when born] was entered religious marriage between Jew Eliayash Markovich and Jewess Tauba Ryfka Elfenbejm
Rabbi and witnesses signed, bridegroom declared that they are illiterate.

NOTE made by reviewer: Even if they could write Yiddish, if they couldn’t read or write Russian, they were deemed illiterate.