Elizabeth, I'm a bit puzzled that you posted this query here.The Germany message board would have been the appropriate message board, and you would have been much more likely to find people who could answer your question there than here.But I happened to see it here, so I'll reply to it.
It would have made things easier had you included more information, such as the names of the people who were from this town, and if any of them emigrated to America, and if so, where in America they lived, etc.So I'll have to answer your query based upon the information you provided.Please bear that in mind.
I feel very sure that you are mistaken about the town you're interested in here having been called Niederwitz.I say that because having read and replied to your query about Possnitz's Catholic church records, I know that you're interested in people from Possnitz in Upper Silesia, and you say that the town you're interested in now was presumably located in Silesia as well.(That's something else you failed to include in your query, on what you're basing the presumption that this town was in Silesia.It's always of the utmost importance, Elizabeth, when posting a query to include every bit of information you have up front if you want somebody to really be able to assist you properly.)
There was only one Niederwitz in all of Germany, and that was a very small village that was actually administered as part of the city of Goldap, located in what was until 1945 the Prussian province of East Prussia.East Prussia was located in northeasternmost Germany, nowhere even remotely in the vicinity of Silesia!So my feeling is that the source -- (and you failed to cite your source here, something also important) -- that gave you the name Niederwitz was an erroneous source.It was simply a mistake.
There was a town located in Upper Silesia, just like Possnitz was, that was called NITTERWITZ.I feel quite sure, all things considered, that Nitterwitz is the town you're actually interested in now.
Nitterwitz was located in the District (in German: Kreis) of Grottkau in Upper Silesia.In 1939, Nitterwitz was a village of about 300 people.Nitterwitz belonged to the Roman Catholic parish of Ottmachau.Ottmachau's Catholic church records are available on microfilm through your Mormon Family History Center.
Nitterwitz, by the way, was located about 50 miles or 85 km northwest of Possnitz.
Nitterwitz is now known by the Polish name Nieradowice.Grottkau is now known by the Polish name Grodkow.Ottmachau is now known by the Polish name Otmuchow.
(My background, by the way, includes six years studying history at the University of Munich in Germany, in case you may have been wondering where my historical knowledge comes from.)