Jerry, I think you may be talking about the New Hope Cemetery which is located in Paulding County GA. The cemetery is near East Paulding Drive and SR 120 and is located East of Dallas, GA. The elementary school is across the highway (SR 120)from the cemetary. I've been there several times and there is a Ga Historical Marker indicating the dates of the Battle of New Hope. I am not familiar with a marker for a mass grave but that is not to say there isn't one. Located in the cemetery are several markers indicating the burial of unknown Confederate dead. To my understanding most Union were taken to Marietta National Cemetery and reintered there. In addition, New Hope is very near Pickett's Mill where another major battle was fought and is now part of the National Park Service. A museum is now located at this park and also has a very informative self guided walking tour.