Searching in the archives in town Poznań (Posen)to know, I came across some information on your great-grandparents married Simon Gmerek & Agnes Szymańska. According to these documents were married in 1879 in Parafii Katolickiej in the village Środa, Agnes was 16 years old, and Simon 26 years. Register books of this entry can be found in "Archiwum Archidiecezjalne w Poznaniu." Address of the page you will find on the internet. Try to:
http://bindweed.man.poznan.pl/posen/- but only in polish language.
I think there is a marriage certificate Gmerek Rosalia and Joseph Powiński , from the year 1878, in Parafia Katolicka in the village Czerlejno. She was 20 years old, and he was 25 years.
Besides verb "gmerać" means rummage, but "gmerek" is a noun and it was sign or seal meant belonging to the family. It was a kind of signature. Was placed on graves, objects and documents. Gmerek mark as a signature on the documents can be found in the sixteenth century. I'm from Polish so I know this for sure.
I am not registered on this site permanently. If you need any help you can contact me at:
jjnowicka@poczta.onet.pl.
My great-grandfather was Valentine Gmerek from Kołaczkowo, His wife was Helena (Stasiak).