Forgive me as I lost the link to the site that reported the following excerpted information.
This is about the Grave Posts or Markers. The top of the square column is always beveled if the deceased was married. The front side of a married man's marker is higher. If it's the grave of a married woman, the front side is lower and the back higher. Young boys were marked with an orb. Young girls with a four-pronged crown. The horizontal scores on the markers front indicated the age of the deceased.
A family marker is a combination of the male and female marker with a top shaped like a roof.
Some authors say that wooden grave post were embraced by the Protestants but there are posts older than Protestantism, so ???