The county courthouse, Jacksonville, N.C., do maintain original material with SOME dating back into the late 1700, early 1800s, and later.
Official records were lost, burned and in some cases deliberatly destroyed due to wars, fires and floods.
The State Archives maintain a lot of information but, do not have files separated for specific names. They do not have a great deal of material in reference to Onslow County's early years.
I have located the name "William Clifton," in one of my primary referance material. He lived in what we call now, Jacksonville, N.C. He set up household ca.1768.
Could your John be William? Or, John's father?
I agree with the previous post. Too many missing graves and cemeteries throughout Onslow County. Stone grave markers were used during the late 1700s to present. Many used rocks, metelic items, perinial flowers and, as previously stated, wooden markers.
I hope my imput helps you in your adventure.
Here is my primary Internet site so you can see what I do in Onslow County.http://www.resurrection-mission.com