Tombstone Tuesday: Or lack there of?

Back at Christmastime, I posted about my 3rd Great Grandfather, Jonas Robinson, and what I thought was his grave:  Is That You, Jonas?  I have come to learn that the grave I took a picture of is not where Jonas is buried.  Not only that, but there's no gravestone at all!  I sent a donation to the organization that is maintaining the records for the cemetery (which is in serious disrepair) and in return they did some extra research for me, including taking a picture of the actual grave.

Jonas Robinson's Grave at Greenwood Cemetery

I suppose the item buried just above the plot could turn out to be his gravestone once it's unearthed.  I wonder how long it will take for the to start uprighting the gravestones?  I also have a list of about 100 other Robinsons buried in this cemetery to go through to figure out if they are family.