I have some questions about:

Geziena Alberts Pool and her family:
(She had one sister that was younger than her: Sijke Alberts Pool.)
Geziena was born as the daughter of Albert Jans Pool and Jantje Willems Wolthuis. In 1824 In Kröddeburen, Groningen Netherlands. When she was 23 years of age, in 1847, she had a child: Jacob Pieters Pool. This is for sure.
But now I have some problems:
Who was the father?
Where does the name “Pieters” come from? (“Pieters” means: son of Pieter.)
The next thing I know is she gets married in 1865 with the widower Tjipke de Vries. They have a child together and they call him (in 1866) Roelf de Vries.
Shortly after the birth of the child they pack their things and travel, together with Jacob, to the US to emigrate. They arrive in Chicago and there the baby dies. Jacob is 20 years old now and is a shoemaker by profession.
Soon after they travel to Springlake MI and stay there for the rest of their lives. In 1869 Geziena again has a baby (she is 45 years old now!) and they call him again: Roelf (Ralph).
Geziena Alberts Pool died in 1911 in Springlake MI. Last year I found their graves in Springlake MI.
But that is still a puzzle. What I discovered is the owner of the grave, the man who bought it: Jacob P. Pool.

In the cemetery records it says:

POOL Jacob
Gesiena Jan. 1, 1869
Ralph Jan. 17, 1895
Source: SPRING LAKE CEMETERY (East Side) Spring Lake Twp, Section 14.

Until now, what I do not understand is who is this Geziena and who is this Ralph?
Roelf, the second son with that name of Geziena and Tjipke had as his last name of course: DeVries. Not Pool. There is nothing readable on the gravestones anymore. I checked that. Is it possible that this person buried in Springlake is Ralph DeVries?
If not: who is it?
Even harder is the puzzle of Geziena Jan. 1, 1869. It is not Geziena Alberts. She died in 1911. So who was it?
And: where are Geziena Alberts and her husband Tjipke de Vries Buried?
May questions. I hope anyone can help me with this.

Tjipke Alberts de Vries, born on 06-07-1812 in Usquert, died circa 1871 in Springlake MI.
Married (1) before 1840 to Janna Hendriks Benes, died on 29-02-1864 in Usquert.
Married (2) at the age of 52 on 02-02-1865 in Stedum to Geziena Alberts Pool, 40 years old, born on 05-10-1824 in St Annen, christened on 07-10-1824 in St Annen, died on 07-05-1911 in Springlake MI at the age of 86.
Daughter of Albert Jans Pool, and Jantje Willems Wolthuis.
From the first marriage:
1. Geert de Vries, born circa 1840 in Stedum.
Married on 26-04-1862 in Usquert to Geertruit Klaverdijk, 24 years old, born on 14-04-1838 in Usquert, daughter of Meerten Klaassens Klaverdijk, and Geessien Jacobs Valkema.
From the second marriage:
2. Roelf de Vries, born on 05-08-1866 in Usquert, died on 21-08-1867 in Chicago at the age of 1.
3. Roelf (Ralph) de Vries, born on 08-01-1869 in Springlake MI.

greetings from Erik Stam
http://www.stamek.nl