I am not sure that I am researching the same John Corey or Cory that you are but the name Zadoc caught my attention.Let me tell you about my John.
John W Cory was born abt 1818 in OH or VA.I want to think OH because his daughter through whom I descend was born in OH. I have a marriage certificate for John W Corey and Margarett Grimm (both were widowed) and Zadoc is listed as his father.On this record it states that he was born in Wood Co, VA(WV).They were married in Wirt Co, WV on Nov 25th of 1866. It also mentions that John was an engineer.I think that might be a big help.
I would like any info on the cemetery you mentioned...name...location....I live close enough to investigate.Thanks!!