We have just posted a listing of burials for the City cemetery of South Pittsburg, TN. Unfortunately the list has no dates, but there are several Zwald's buried there and a number of ladies with a middle initial of Z. Could be a middle name but I'm pretty sure a couple of these were Zwalds.
This is at the Marion County Tennessee History & Genealogy website:
http://www.rootsweb.com/~tnmario2/citycemetery.html