Thank you, Mary
I didn't finish editing the profiles yet, so I didn't put the hyperlinks there.
I'd been searching for "Рековский Семеновка", and came across two valuable sites, http://wolgadeutschen.borda.ru/?1-19-0-00000114-000-40-0 (mainly in Russian) and http://www.semenowka3.blogspot.com/ (Spanish).
However, no Georg Rekowski seems to be found in Kamenka parish birth records for 1811-1828, and there are *two* Joseph Rekowskis born there in 1817 (not 1818, as at http://www.semenowka3.blogspot.com/ ).
Please, also remember that there's no proof yet that Ignaz Rekowski found at http://www.semenowka3.blogspot.com/ is the Ignaz Rekowski who was your great-grandfather, however likely it is.
Btw, do you happen to know about your great-grandmother Mary Schaff's origin? I've just noticed that her surname sounds very much alike the common surname of Semyonovka residents, Schaab. Probably she have come to the U.S. together with Joseph "Игнацович" Rekofke, or joined him later.
Mary Schaff did not come to the US. The only reason I know her name is because here in the US only one document (Social Security) required my grandfather's parents' names. Unfortunetly, I know nothing of her. I fell very fortunate just to know their names. My family believes Ernst died in the early 1900's. Joseph is believed to have had one brother and two sisters.