This is the grave marker for my great-great-grandmother, Anna Helena (Schmitt) Fitzler.
I have not yet been able to locate her husband's grave. That would be my great-great-grandfather John Wymer Fitzler. I'm pretty sure he died in Marshall Co., IL. Thanks to a recently found obituary for Helena that I wrote about here, I've managed to narrow down the date of his death to around 1892. I'll find him eventually.