What is the symbol of short story carved table by Mary Peterson?

The symbol on the short story carved table by Mary Peterson is called the "Chi Rho" symbol. It is an early Christian symbol consisting of the first two letters of the Greek word for "Christ" ("ΧΡΙΣΤΟΣ") superimposed on each other: chi (Χ) and rho (Ρ). The Chi Rho symbol was often used in early Christian art and architecture as a way to identify Christian spaces and objects.