palimpsest

noun       |    pa limp sest    |   \'pa-ləm(p)-sest, pə-'lim(p)-\

1. writing material (such as a parchment or tablet used one or more times after earlier writing has been erased.
2. something having usually diverse layers or aspects apparent beneath the surface.

• Canada ... is a palimpsest, an overlay of classes and generations. — Margarat Atwood
•  too short a time to get to know the palimpsest of Genevan societies, let alone those of Switzerland. —George Steiner

definition via Merriam-Webster