Great great grandfather was from Posen Germany about that same time. He came to America 1860 time frame. I know they settled in Wisconsin, Later moved to upstate NY. I remember Dunkirk NY as a kid. I know Carl Fred Eggert was a name that was mentioned alot. not sure if they are one in the same.. I will check with my aunt.
other names that were mentioned. surname Martin.
believe they came over and got married late 1860s.. did the land lottery thing in Wisconsin. Wife was 17-19 years of age.
anyway if you want to contact .... firstname.lastname@example.org
I will be compiling as much info as soon as I can.