It's part of the inscription.
The rock is usually referred to as a tombstone or headstone when it marks a person's grave. It typically displays the individual's name, dates of birth and death, and sometimes a message or epitaph.
You are more likely to find an epitaph on a gravestone. An epitaph is a short text honoring the deceased, often accompanying their name and dates. An epoch, on the other hand, refers to a distinct period of time in history.
Epitaph Bread and Salt - 2013 was released on: USA: 30 July 2013 (Chicago, Illinois)
Tomb often contain saying in addition to the dates of birth and death. Known as epitaphs, these sayings are commemorations of the dead persons.
Tombstone Territory - 1957 Red Terror of Tombstone - 3.1 was released on: USA: 9 October 1959
Tombstone Territory - 1957 Payroll to Tombstone 2-3 was released on: USA: 27 March 1959
Epitaph - 2011 I was released on: USA: 18 October 2011 (4th Annual Kentucky Short Film and Video Showcase)
1945 -1994
Batman - 1966 The Joker's Epitaph 2-48 was released on: USA: 16 February 1967
Tombstone Canyon - 1932 was released on: USA: 25 December 1932
West of Tombstone - 1942 was released on: USA: 15 January 1942
Shadows of Tombstone - 1953 was released on: USA: 28 September 1953