Destroyed is a possible status of a survey mark. Destroyed can mean that the marker no longer exists at all, or it can mean that the marker has been moved out of its position. A mark that has moved even a distance as little as a fraction of an inch destroys its usefulness as a marker of a position.
No survey marks should be considered to be destroyed unless the ["NGS"] officially classifies the mark as destroyed. They are the final judge of the destroyed classification. They are quite conservative in this evaluation. For instance, even if the mark's location has been paved for a parking lot, the mark may still be under the pavement and the NGS will probably not consider it destroyed.